I/O control¶

The following parameters concern the files which are read and written.

-h, --help

Show summary of usage and exit.

-o=filename, --outfile=filename

Name of the output file (only if a single input file is being processed). If no output file is specified, and output is not redirected to the standard output, the output will go to filename.tdy.

-st, --standard-output

Perltidy must be able to operate on an arbitrarily large number of files in a single run, with each output being directed to a different output file. Obviously this would conflict with outputting to the single standard output device, so a special flag, -st, is required to request outputting to the standard output. For example,

  perltidy somefile.pl -st >somefile.new.pl
    

This option may only be used if there is just a single input file. The default is -nst or --nostandard-output.

-se, --standard-error-output

If perltidy detects an error when processing file somefile.pl, its default behavior is to write error messages to file somefile.pl.ERR. Use -se to cause all error messages to be sent to the standard error output stream instead. This directive may be negated with -nse. Thus, you may place -se in a .perltidyrc and override it when desired with -nse on the command line.

-oext=ext, --output-file-extension=ext

Change the extension of the output file to be ext instead of the default tdy (or html in case the --html option is used). See "Specifying File Extensions".

-opath=path, --output-path=path

When perltidy creates a filename for an output file, by default it merely appends an extension to the path and basename of the input file. This parameter causes the path to be changed to path instead.

The path should end in a valid path separator character, but perltidy will try to add one if it is missing.

For example

 perltidy somefile.pl -opath=/tmp/
    

will produce /tmp/somefile.pl.tdy. Otherwise, somefile.pl.tdy will appear in whatever directory contains somefile.pl.

If the path contains spaces, it should be placed in quotes.

This parameter will be ignored if output is being directed to standard output, or if it is being specified explicitly with the -o=s parameter.

-b, --backup-and-modify-in-place

Modify the input file or files in-place and save the original with the extension .bak. Any existing .bak file will be deleted. See next item for changing the default backup extension.

A -b flag will be ignored if input is from standard input, or if the -html flag is set.

-bext=ext, --backup-file-extension=ext

Change the extension of the backup file to be something other than the default .bak. See "Specifying File Extensions".

-w, --warning-output

Setting -w causes any non-critical warning messages to be reported as errors. These include messages about possible pod problems, possibly bad starting indentation level, and cautions about indirect object usage. The default, -nw or --nowarning-output, is not to include these warnings.

-q, --quiet

Deactivate error messages and syntax checking (for running under an editor).

For example, if you use a vi-style editor, such as vim, you may execute perltidy as a filter from within the editor using something like

 :n1,n2!perltidy -q
    

where "n1,n2" represents the selected text. Without the -q flag, any error message may mess up your screen, so be prepared to use your "undo" key.

-log, --logfile

Save the .LOG file, which has many useful diagnostics. Perltidy always creates a .LOG file, but by default it is deleted unless a program bug is suspected. Setting the -log flag forces the log file to be saved.

-g=n, --logfile-gap=n

Set maximum interval between input code lines in the logfile. This purpose of this flag is to assist in debugging nesting errors. The value of "n" is optional. If you set the flag -g without the value of "n", it will be taken to be 1, meaning that every line will be written to the log file. This can be helpful if you are looking for a brace, paren, or bracket nesting error.

Setting -g also causes the logfile to be saved, so it is not necessary to also include -log.

If no -g flag is given, a value of 50 will be used, meaning that at least every 50th line will be recorded in the logfile. This helps prevent excessively long log files.

Setting a negative value of "n" is the same as not setting -g at all.

-npro --noprofile

Ignore any .perltidyrc command file. Normally, perltidy looks first in your current directory for a .perltidyrc file of parameters. (The format is described below). If it finds one, it applies those options to the initial default values, and then it applies any that have been defined on the command line. If no .perltidyrc file is found, it looks for one in your home directory.

If you set the -npro flag, perltidy will not look for this file.

-pro=filename or --profile=filename

To simplify testing and switching .perltidyrc files, this command may be used to specify a configuration file which will override the default name of .perltidyrc. There must not be a space on either side of the '=' sign. For example, the line

   perltidy -pro=testcfg
    

would cause file testcfg to be used instead of the default .perltidyrc.

-opt, --show-options

Write a list of all options used to the .LOG file. Please see --dump-options for a simpler way to do this.

-f, --force-read-binary

Force perltidy to process binary files. To avoid producing excessive error messages, perltidy skips files identified by the system as non-text. However, valid perl scripts containing binary data may sometimes be identified as non-text, and this flag forces perltidy to process them.

Basic Options¶

-l=n, --maximum-line-length=n

The default maximum line length is n=80 characters. Perltidy will try to find line break points to keep lines below this length. However, long quotes and side comments may cause lines to exceed this length. Setting -l=0 is equivalent to setting -l=(a large number).

-i=n, --indent-columns=n

Use n columns per indentation level (default n=4).

tabs

Using tab characters will almost certainly lead to future portability and maintenance problems, so the default and recommendation is not to use them. For those who prefer tabs, however, there are two different options.

Except for possibly introducing tab indentation characters, as outlined below, perltidy does not introduce any tab characters into your file, and it removes any tabs from the code (unless requested not to do so with -fws). If you have any tabs in your comments, quotes, or here-documents, they will remain.

-syn, --check-syntax

This flag causes perltidy to run "perl -c -T" to check syntax of input and output. (To change the flags passed to perl, see the next item, -pscf). The results are written to the .LOG file, which will be saved if an error is detected in the output script. The output script is not checked if the input script has a syntax error. Perltidy does its own checking, but this option employs perl to get a "second opinion".

If perl reports errors in the input file, they will not be reported in the error output unless the --warning-output flag is given.

The default is not to do this type of syntax checking (although perltidy will still do as much self-checking as possible). The reason is that it causes all code in BEGIN blocks to be executed, for all modules being used, and this opens the door to security issues and infinite loops when running perltidy.

-pscf=s, -perl-syntax-check-flags=s

When perl is invoked to check syntax, the normal flags are "-c -T". In addition, if the -x flag is given to perltidy, then perl will also be passed a -x flag. It should not normally be necessary to change these flags, but it can be done with the -pscf=s flag. For example, if the taint flag, "-T", is not wanted, the flag could be set to be just -pscf=-c.

Perltidy will pass your string to perl with the exception that it will add a -c and -x if appropriate. The .LOG file will show exactly what flags were passed to perl.

-io, --indent-only

This flag is used to deactivate all formatting and line break changes within non-blank lines of code. When it is in effect, the only change to the script will be to the indentation and blank lines. And any flags controlling whitespace and newlines will be ignored. You might want to use this if you are perfectly happy with your whitespace and line breaks, and merely want perltidy to handle the indentation. (This also speeds up perltidy by well over a factor of two, so it might be useful when perltidy is merely being used to help find a brace error in a large script).

Setting this flag is equivalent to setting --freeze-newlines and --freeze-whitespace.

If you also want to keep your existing blank lines exactly as they are, you can add --freeze-blank-lines.

-ole=s, --output-line-ending=s

where s="win", "dos", "unix", or "mac". This flag tells perltidy to output line endings for a specific system. Normally, perltidy writes files with the line separator character of the host system. The "win" and "dos" flags have an identical result.

-ple, --preserve-line-endings

This flag tells perltidy to write its output files with the same line endings as the input file, if possible. It should work for dos, unix, and mac line endings. It will only work if perltidy input comes from a filename (rather than stdin, for example). If perltidy has trouble determining the input file line ending, it will revert to the default behavior of using the line ending of the host system.

Code Indentation Control¶

-ci=n, --continuation-indentation=n

Continuation indentation is extra indentation spaces applied when a long line is broken. The default is n=2, illustrated here:

 my $level =   # -ci=2      
   ( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
    

The same example, with n=0, is a little harder to read:

 my $level =   # -ci=0    
 ( $max_index_to_go >= 0 ) ? $levels_to_go[0] : $last_output_level;
    

The value given to -ci is also used by some commands when a small space is required. Examples are commands for outdenting labels, -ola, and control keywords, -okw.

When default values are not used, it is suggested that the value n given with -ci=n be no more than about one-half of the number of spaces assigned to a full indentation level on the -i=n command.

-sil=n --starting-indentation-level=n

By default, perltidy examines the input file and tries to determine the starting indentation level. While it is often zero, it may not be zero for a code snippet being sent from an editing session. If the default method does not work correctly, or you want to change the starting level, use -sil=n, to force the starting level to be n.

List indentation using -lp, --line-up-parentheses

By default, perltidy indents lists with 4 spaces, or whatever value is specified with -i=n. Here is a small list formatted in this way:

    # perltidy (default)
    @month_of_year = (
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
        'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
    );
    

Use the -lp flag to add extra indentation to cause the data to begin past the opening parentheses of a sub call or list, or opening square bracket of an anonymous array, or opening curly brace of an anonymous hash. With this option, the above list would become:

    # perltidy -lp
    @month_of_year = (
                       'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
                       'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
    );
    

If the available line length (see -l=n ) does not permit this much space, perltidy will use less. For alternate placement of the closing paren, see the next section.

This option has no effect on code BLOCKS, such as if/then/else blocks, which always use whatever is specified with -i=n. Also, the existence of line breaks and/or block comments between the opening and closing parens may cause perltidy to temporarily revert to its default method.

Note: The -lp option may not be used together with the -t tabs option. It may, however, be used with the -et=n tab method.

In addition, any parameter which significantly restricts the ability of perltidy to choose newlines will conflict with -lp and will cause -lp to be deactivated. These include -io, -fnl, -nanl, and -ndnl. The reason is that the -lp indentation style can require the careful coordination of an arbitrary number of break points in hierarchical lists, and these flags may prevent that.

-cti=n, --closing-token-indentation

The -cti=n flag controls the indentation of a line beginning with a ")", "]", or a non-block "}". Such a line receives:

 -cti = 0 no extra indentation (default)
 -cti = 1 extra indentation such that the closing token
        aligns with its opening token.
 -cti = 2 one extra indentation level if the line looks like:
        );  or  ];  or  };
 -cti = 3 one extra indentation level always
    

The flags -cti=1 and -cti=2 work well with the -lp flag (previous section).

    # perltidy -lp -cti=1
    @month_of_year = (
                       'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
                       'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
                     );
    # perltidy -lp -cti=2
    @month_of_year = (
                       'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun',
                       'Jul', 'Aug', 'Sep', 'Oct', 'Nov', 'Dec'
                       );
    

These flags are merely hints to the formatter and they may not always be followed. In particular, if -lp is not being used, the indentation for cti=1 is constrained to be no more than one indentation level.

If desired, this control can be applied independently to each of the closing container token types. In fact, -cti=n is merely an abbreviation for -cpi=n -csbi=n -cbi=n, where: -cpi or --closing-paren-indentation controls )'s, -csbi or --closing-square-bracket-indentation controls ]'s, -cbi or --closing-brace-indentation controls non-block }'s.

-icp, --indent-closing-paren

The -icp flag is equivalent to -cti=2, described in the previous section. The -nicp flag is equivalent -cti=0. They are included for backwards compatability.

-icb, --indent-closing-brace

The -icb option gives one extra level of indentation to a brace which terminates a code block . For example,

        if ($task) {
            yyy();
            }    # -icb
        else {
            zzz();
            }
    

The default is not to do this, indicated by -nicb.

-olq, --outdent-long-quotes

When -olq is set, lines which is a quoted string longer than the value maximum-line-length will have their indentation removed to make them more readable. This is the default. To prevent such out-denting, use -nolq or --nooutdent-long-lines.

-oll, --outdent-long-lines

This command is equivalent to --outdent-long-quotes and --outdent-long-comments, and it is included for compatibility with previous versions of perltidy. The negation of this also works, -noll or --nooutdent-long-lines, and is equivalent to setting -nolq and -nolc.

Outdenting Labels: -ola, --outdent-labels

This command will cause labels to be outdented by 2 spaces (or whatever -ci has been set to), if possible. This is the default. For example:

        my $i;
      LOOP: while ( $i = <FOTOS> ) {
            chomp($i);
            next unless $i;
            fixit($i);
        }
    

Use -nola to not outdent labels.

Outdenting Keywords

Whitespace Control¶

Whitespace refers to the blank space between variables, operators, and other code tokens.

-fws, --freeze-whitespace

This flag causes your original whitespace to remain unchanged, and causes the rest of the whitespace commands in this section, the Code Indentation section, and the Comment Control section to be ignored.

Tightness of curly braces, parentheses, and square brackets.

Here the term "tightness" will mean the closeness with which pairs of enclosing tokens, such as parentheses, contain the quantities within. A numerical value of 0, 1, or 2 defines the tightness, with 0 being least tight and 2 being most tight. Spaces within containers are always symmetric, so if there is a space after a "(" then there will be a space before the corresponding ")".

The -pt=n or --paren-tightness=n parameter controls the space within parens. The example below shows the effect of the three possible values, 0, 1, and 2:

 if ( ( my $len_tab = length( $tabstr ) ) > 0 ) {  # -pt=0
 if ( ( my $len_tab = length($tabstr) ) > 0 ) {    # -pt=1 (default)
 if ((my $len_tab = length($tabstr)) > 0) {        # -pt=2
    

When n is 0, there is always a space to the right of a '(' and to the left of a ')'. For n=2 there is never a space. For n=1, the default, there is a space unless the quantity within the parens is a single token, such as an identifier or quoted string.

Likewise, the parameter -sbt=n or --square-bracket-tightness=n controls the space within square brackets, as illustrated below.

 $width = $col[ $j + $k ] - $col[ $j ];  # -sbt=0
 $width = $col[ $j + $k ] - $col[$j];    # -sbt=1 (default)
 $width = $col[$j + $k] - $col[$j];      # -sbt=2
    

Curly braces which do not contain code blocks are controlled by the parameter -bt=n or --brace-tightness=n.

 $obj->{ $parsed_sql->{ 'table' }[0] };    # -bt=0
 $obj->{ $parsed_sql->{'table'}[0] };      # -bt=1 (default)
 $obj->{$parsed_sql->{'table'}[0]};        # -bt=2
    

And finally, curly braces which contain blocks of code are controlled by the parameter -bbt=n or --block-brace-tightness=n as illustrated in the example below.

 %bf = map { $_ => -M $_ } grep { /\.deb$/ } dirents '.'; # -bbt=0 (default)
 %bf = map { $_ => -M $_ } grep {/\.deb$/} dirents '.';   # -bbt=1
 %bf = map {$_ => -M $_} grep {/\.deb$/} dirents '.';     # -bbt=2
    

-sts, --space-terminal-semicolon

Some programmers prefer a space before all terminal semicolons. The default is for no such space, and is indicated with -nsts or --nospace-terminal-semicolon.

        $i = 1 ;     #  -sts
        $i = 1;      #  -nsts   (default)
    

-sfs, --space-for-semicolon

Semicolons within for loops may sometimes be hard to see, particularly when commas are also present. This option places spaces on both sides of these special semicolons, and is the default. Use -nsfs or --nospace-for-semicolon to deactivate it.

 for ( @a = @$ap, $u = shift @a ; @a ; $u = $v ) {  # -sfs (default)
 for ( @a = @$ap, $u = shift @a; @a; $u = $v ) {    # -nsfs
    

-asc, --add-semicolons

Setting -asc allows perltidy to add any missing optional semicolon at the end of a line which is followed by a closing curly brace on the next line. This is the default, and may be deactivated with -nasc or --noadd-semicolons.

-dsm, --delete-semicolons

Setting -dsm allows perltidy to delete extra semicolons which are simply empty statements. This is the default, and may be deactivated with -ndsm or --nodelete-semicolons. (Such semicolons are not deleted, however, if they would promote a side comment to a block comment).

-aws, --add-whitespace

Setting this option allows perltidy to add certain whitespace improve code readability. This is the default. If you do not want any whitespace added, but are willing to have some whitespace deleted, use -naws. (Use -fws to leave whitespace completely unchanged).

-dws, --delete-old-whitespace

Setting this option allows perltidy to remove some old whitespace between characters, if necessary. This is the default. If you do not want any old whitespace removed, use -ndws or --nodelete-old-whitespace.

Detailed whitespace controls around tokens

For those who want more detailed control over the whitespace around tokens, there are four parameters which can directly modify the default whitespace rules built into perltidy for any token. They are:

-wls=s or --want-left-space=s,

-nwls=s or --nowant-left-space=s,

-wrs=s or --want-right-space=s,

-nwrs=s or --nowant-right-space=s.

These parameters are each followed by a quoted string, s, containing a list of token types. No more than one of each of these parameters should be specified, because repeating a command-line parameter always overwrites the previous one before perltidy ever sees it.

To illustrate how these are used, suppose it is desired that there be no space on either side of the token types = + - / *. The following two parameters would specify this desire:

  -nwls="= + - / *"    -nwrs="= + - / *"
    

(Note that the token types are in quotes, and that they are separated by spaces). With these modified whitespace rules, the following line of math:

  $root = -$b + sqrt( $b * $b - 4. * $a * $c ) / ( 2. * $a );
    

becomes this:

  $root=-$b+sqrt( $b*$b-4.*$a*$c )/( 2.*$a );
    

These parameters should be considered to be hints to perltidy rather than fixed rules, because perltidy must try to resolve conflicts that arise between them and all of the other rules that it uses. One conflict that can arise is if, between two tokens, the left token wants a space and the right one doesn't. In this case, the token not wanting a space takes priority.

It is necessary to have a list of all token types in order to create this type of input. Such a list can be obtained by the command --dump-token-types. Also try the -D flag on a short snippet of code and look at the .DEBUG file to see the tokenization.

WARNING Be sure to put these tokens in quotes to avoid having them misinterpreted by your command shell.

Space between specific keywords and opening paren

When an opening paren follows a Perl keyword, no space is introduced after the keyword, unless it is (by default) one of these:

   my local our and or eq ne if else elsif until unless 
   while for foreach return switch case given when
    

These defaults can be modified with two commands:

-sak=s or --space-after-keyword=s adds keywords.

-nsak=s or --nospace-after-keyword=s removes keywords.

where s is a list of keywords (in quotes if necessary). For example,

  my ( $a, $b, $c ) = @_;    # default
  my( $a, $b, $c ) = @_;     # -nsak="my local our"
    

To put a space after all keywords, see the next item.

Space between all keywords and opening parens

When an opening paren follows a function or keyword, no space is introduced after the keyword except for the keywords noted in the previous item. To always put a space between a function or keyword and its opening paren, use the command:

-skp or --space-keyword-paren

You will probably also want to use the flag -sfp (next item) too.

Space between all function names and opening parens

When an opening paren follows a function the default is not to introduce a space. To cause a space to be introduced use:

-sfp or --space-function-paren

  myfunc( $a, $b, $c );    # default 
  myfunc ( $a, $b, $c );   # -sfp
    

You will probably also want to use the flag -skp (previous item) too.

Trimming whitespace around "qw" quotes

-tqw or --trim-qw provide the default behavior of trimming spaces around multi-line "qw" quotes and indenting them appropriately.

-ntqw or --notrim-qw cause leading and trailing whitespace around multi-line "qw" quotes to be left unchanged. This option will not normally be necessary, but was added for testing purposes, because in some versions of perl, trimming "qw" quotes changes the syntax tree.

Comment Controls¶

Perltidy has a number of ways to control the appearance of both block comments and side comments. The term block comment here refers to a full-line comment, whereas side comment will refer to a comment which appears on a line to the right of some code.

-ibc, --indent-block-comments

Block comments normally look best when they are indented to the same level as the code which follows them. This is the default behavior, but you may use -nibc to keep block comments left-justified. Here is an example:

             # this comment is indented      (-ibc, default)
             if ($task) { yyy(); }
    

The alternative is -nibc:

 # this comment is not indented              (-nibc)
             if ($task) { yyy(); }
    

See also the next item, -isbc, as well as -sbc, for other ways to have some indented and some outdented block comments.

-isbc, --indent-spaced-block-comments

If there is no leading space on the line, then the comment will not be indented, and otherwise it may be.

If both -ibc and -isbc are set, then -isbc takes priority.

-olc, --outdent-long-comments

When -olc is set, lines which are full-line (block) comments longer than the value maximum-line-length will have their indentation removed. This is the default; use -nolc to prevent outdenting.

-msc=n, --minimum-space-to-comment=n

Side comments look best when lined up several spaces to the right of code. Perltidy will try to keep comments at least n spaces to the right. The default is n=4 spaces.

-fpsc=n, --fixed-position-side-comment=n

This parameter tells perltidy to line up side comments in column number n whenever possible. The default, n=0, is not do do this.

-hsc, --hanging-side-comments

By default, perltidy tries to identify and align "hanging side comments", which are something like this:

        my $IGNORE = 0;    # This is a side comment
                           # This is a hanging side comment
                           # And so is this
    

A comment is considered to be a hanging side comment if (1) it immediately follows a line with a side comment, or another hanging side comment, and (2) there is some leading whitespace on the line. To deactivate this feature, use -nhsc or --nohanging-side-comments. If block comments are preceded by a blank line, or have no leading whitespace, they will not be mistaken as hanging side comments.

Closing Side Comments

A closing side comment is a special comment which perltidy can automatically create and place after the closing brace of a code block. They can be useful for code maintenance and debugging. The command -csc (or --closing-side-comments) adds or updates closing side comments. For example, here is a small code snippet

        sub message {
            if ( !defined( $_[0] ) ) {
                print("Hello, World\n");
            }
            else {
                print( $_[0], "\n" );
            }
        }
    

And here is the result of processing with "perltidy -csc":

        sub message {
            if ( !defined( $_[0] ) ) {
                print("Hello, World\n");
            }
            else {
                print( $_[0], "\n" );
            }
        } ## end sub message
    

A closing side comment was added for "sub message" in this case, but not for the "if" and "else" blocks, because they were below the 6 line cutoff limit for adding closing side comments. This limit may be changed with the -csci command, described below.

The command -dcsc (or --delete-closing-side-comments) reverses this process and removes these comments.

Several commands are available to modify the behavior of these two basic commands, -csc and -dcsc:

Static Block Comments

Static block comments are block comments with a special leading pattern, "##" by default, which will be treated slightly differently from other block comments. They effectively behave as if they had glue along their left and top edges, because they stick to the left edge and previous line when there is no blank spaces in those places. This option is particularly useful for controlling how commented code is displayed.

    @month_of_year = (    # -sbc (default)
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
    ##  'Dec', 'Nov'
        'Nov', 'Dec');

    @month_of_year = (   # -nsbc
        'Jan', 'Feb', 'Mar', 'Apr', 'May', 'Jun', 'Jul', 'Aug', 'Sep', 'Oct',
  
        ##  'Dec', 'Nov'
        'Nov', 'Dec'
    );

Static Side Comments

Static side comments are side comments with a special leading pattern. This option can be useful for controlling how commented code is displayed when it is a side comment.

Skipping Selected Sections of Code¶

Selected lines of code may be passed verbatim to the output without any formatting. This feature is enabled by default but can be disabled with the --noformat-skipping or -nfs flag. It should be used sparingly to avoid littering code with markers, but it might be helpful for working around occasional problems. For example it might be useful for keeping the indentation of old commented code unchanged, keeping indentation of long blocks of aligned comments unchanged, keeping certain list formatting unchanged, or working around a glitch in perltidy.

-fs, --format-skipping

This flag, which is enabled by default, causes any code between special beginning and ending comment markers to be passed to the output without formatting. The default beginning marker is #<<< and the default ending marker is #>>> but they may be changed (see next items below). Additional text may appear on these special comment lines provided that it is separated from the marker by at least one space. For example

 #<<<  do not let perltidy touch this
    my @list = (1,
                1, 1,
                1, 2, 1,
                1, 3, 3, 1,
                1, 4, 6, 4, 1,);
 #>>>
    

The comment markers may be placed at any location that a block comment may appear. If they do not appear to be working, use the -log flag and examine the .LOG file. Use -nfs to disable this feature.

-fsb=string, --format-skipping-begin=string

The -fsb=string parameter may be used to change the beginning marker for format skipping. The default is equivalent to -fsb='#<<<'. The string that you enter must begin with a # and should be in quotes as necessary to get past the command shell of your system. It is actually the leading text of a pattern that is constructed by appending a '\s', so you must also include backslashes for characters to be taken literally rather than as patterns.

Some examples show how example strings become patterns:

 -fsb='#\{\{\{' becomes /^#\{\{\{\s/  which matches  #{{{ but not #{{{{
 -fsb='#\*\*'   becomes /^#\*\*\s/    which matches  #** but not #***
 -fsb='#\*{2,}' becomes /^#\*{2,}\s/  which matches  #** and #*****
    

-fse=string, --format-skipping-end=string

The -fsb=string is the corresponding parameter used to change the ending marker for format skipping. The default is equivalent to -fse='#<<<'.

Line Break Control¶

The parameters in this section control breaks after non-blank lines of code. Blank lines are controlled separately by parameters in the section "Blank Line Control".

-fnl, --freeze-newlines

If you do not want any changes to the line breaks within lines of code in your script, set -fnl, and they will remain fixed, and the rest of the commands in this section and sections "Controlling List Formatting", "Retaining or Ignoring Existing Line Breaks". You may want to use -noll with this.

Note: If you also want to keep your blank lines exactly as they are, you can use the -fbl flag which is described in the section "Blank Line Control".

-ce, --cuddled-else

Enable the "cuddled else" style, in which "else" and "elsif" are follow immediately after the curly brace closing the previous block. The default is not to use cuddled elses, and is indicated with the flag -nce or --nocuddled-else. Here is a comparison of the alternatives:

  if ($task) {
      yyy();
  } else {    # -ce
      zzz();
  }
  if ($task) {
        yyy();
  }
  else {    # -nce  (default)
        zzz();
  }
    

-bl, --opening-brace-on-new-line

Use the flag -bl to place the opening brace on a new line:

  if ( $input_file eq '-' )    # -bl 
  {                          
      important_function();
  }
    

This flag applies to all structural blocks, including named sub's (unless the -sbl flag is set -- see next item).

The default style, -nbl, places an opening brace on the same line as the keyword introducing it. For example,

  if ( $input_file eq '-' ) {   # -nbl (default)
    

-sbl, --opening-sub-brace-on-new-line

The flag -sbl can be used to override the value of -bl for the opening braces of named sub's. For example,

 perltidy -sbl
    

produces this result:

 sub message
 {
    if (!defined($_[0])) {
        print("Hello, World\n");
    }
    else {
        print($_[0], "\n");
    }
 }
    

This flag is negated with -nsbl. If -sbl is not specified, the value of -bl is used.

-asbl, --opening-anonymous-sub-brace-on-new-line

The flag -asbl is like the -sbl flag except that it applies to anonymous sub's instead of named subs. For example

 perltidy -asbl
    

produces this result:

 $a = sub
 {
     if ( !defined( $_[0] ) ) {
         print("Hello, World\n");
     }
     else {
         print( $_[0], "\n" );
     }
 };
    

This flag is negated with -nasbl, and the default is -nasbl.

-bli, --brace-left-and-indent

The flag -bli is the same as -bl but in addition it causes one unit of continuation indentation ( see -ci ) to be placed before an opening and closing block braces.

For example,

        if ( $input_file eq '-' )    # -bli
          {
            important_function();
          }
    

By default, this extra indentation occurs for blocks of type: if, elsif, else, unless, for, foreach, sub, while, until, and also with a preceding label. The next item shows how to change this.

-blil=s, --brace-left-and-indent-list=s

Use this parameter to change the types of block braces for which the -bli flag applies; see "Specifying Block Types". For example, -blil='if elsif else' would apply it to only "if/elsif/else" blocks.

-bar, --opening-brace-always-on-right

The default style, -nbl places the opening code block brace on a new line if it does not fit on the same line as the opening keyword, like this:

        if ( $bigwasteofspace1 && $bigwasteofspace2
          || $bigwasteofspace3 && $bigwasteofspace4 )
        {
            big_waste_of_time();
        }
    

To force the opening brace to always be on the right, use the -bar flag. In this case, the above example becomes

        if ( $bigwasteofspace1 && $bigwasteofspace2
          || $bigwasteofspace3 && $bigwasteofspace4 ) {
            big_waste_of_time();
        }
    

A conflict occurs if both -bl and -bar are specified.

-otr, --opening-token-right and related flags

The -otr flag is a hint that perltidy should not place a break between a comma and an opening token. For example:

    # default formatting
    push @{ $self->{$module}{$key} },
      {
        accno       => $ref->{accno},
        description => $ref->{description}
      };
    # perltidy -otr
    push @{ $self->{$module}{$key} }, {
        accno       => $ref->{accno},
        description => $ref->{description}
      };
    

The flag -otr is actually a synonym for three other flags which can be used to control parens, hash braces, and square brackets separately if desired:

  -opr  or --opening-paren-right
  -ohbr or --opening-hash-brace-right
  -osbr or --opening-square-bracket-right
    

Vertical tightness of non-block curly braces, parentheses, and square brackets.

These parameters control what shall be called vertical tightness. Here are the main points:

    # perltidy -lp -vt=0 -vtc=0
    %romanNumerals = (
                       one   => 'I',
                       two   => 'II',
                       three => 'III',
                       four  => 'IV',
    );
    # perltidy -lp -vt=1 -vtc=0
    %romanNumerals = ( one   => 'I',
                       two   => 'II',
                       three => 'III',
                       four  => 'IV',
    );
    # perltidy -lp -vt=1 -vtc=1
    %romanNumerals = ( one   => 'I',
                       two   => 'II',
                       three => 'III',
                       four  => 'IV', );

    # perltidy -lp -vt=1 
    $init->add(
                mysprintf( "(void)find_threadsv(%s);",
                           cstring( $threadsv_names[ $op->targ ] )
                )
    );
    # perltidy -lp -vt=2 
    $init->add( mysprintf( "(void)find_threadsv(%s);",
                           cstring( $threadsv_names[ $op->targ ] )
                )
    );

    # perltidy -lp -vt=2 -vtc=2
    $init->add( mysprintf( "(void)find_threadsv(%s);",
                           cstring( $threadsv_names[ $op->targ ] ) ) );

-bbvt=n or --block-brace-vertical-tightness=n

The -bbvt=n flag is just like the -vt=n flag but applies to opening code block braces.

 -bbvt=0 break after opening block brace (default). 
 -bbvt=1 do not break unless this would produce more than one 
         step in indentation in a line.
 -bbvt=2 do not break after opening block brace.
    

It is necessary to also use either -bl or -bli for this to work, because, as with other vertical tightness controls, it is implemented by simply overwriting a line ending with an opening block brace with the subsequent line. For example:

    # perltidy -bli -bbvt=0
    if ( open( FILE, "< $File" ) )
      {
        while ( $File = <FILE> )
          {
            $In .= $File;
            $count++;
          }
        close(FILE);
      }
    # perltidy -bli -bbvt=1
    if ( open( FILE, "< $File" ) )
      { while ( $File = <FILE> )
          { $In .= $File;
            $count++;
          }
        close(FILE);
      }
    

By default this applies to blocks associated with keywords if, elsif, else, unless, for, foreach, sub, while, until, and also with a preceding label. This can be changed with the parameter -bbvtl=string, or --block-brace-vertical-tightness-list=string, where string is a space-separated list of block types. For more information on the possible values of this string, see "Specifying Block Types"

For example, if we want to just apply this style to "if", "elsif", and "else" blocks, we could use "perltidy -bli -bbvt=1 -bbvtl='if elsif else'".

There is no vertical tightness control for closing block braces; with the exception of one-line blocks, they will normally remain on a separate line.

-sot, --stack-opening-tokens and related flags

The -sot flag tells perltidy to "stack" opening tokens when possible to avoid lines with isolated opening tokens.

For example:

    # default
    $opt_c = Text::CSV_XS->new(
        {
            binary       => 1,
            sep_char     => $opt_c,
            always_quote => 1,
        }
    );
    # -sot
    $opt_c = Text::CSV_XS->new( {
            binary       => 1,
            sep_char     => $opt_c,
            always_quote => 1,
        }
    );
    

For detailed control of individual closing tokens the following controls can be used:

  -sop  or --stack-opening-paren
  -sohb or --stack-opening-hash-brace
  -sosb or --stack-opening-square-bracket
    

The flag -sot is a synonym for -sop -sohb -sosb.

-sct, --stack-closing-tokens and related flags

The -sct flag tells perltidy to "stack" closing tokens when possible to avoid lines with isolated closing tokens.

For example:

    # default
    $opt_c = Text::CSV_XS->new(
        {
            binary       => 1,
            sep_char     => $opt_c,
            always_quote => 1,
        }
    );
    # -sct
    $opt_c = Text::CSV_XS->new(
        {
            binary       => 1,
            sep_char     => $opt_c,
            always_quote => 1,
        } );
    

The -sct flag is somewhat similar to the -vtc flags, and in some cases it can give a similar result. The difference is that the -vtc flags try to avoid lines with leading opening tokens by "hiding" them at the end of a previous line, whereas the -sct flag merely tries to reduce the number of lines with isolated closing tokens by stacking them but does not try to hide them. For example:

    # -vtc=2
    $opt_c = Text::CSV_XS->new(
        {
            binary       => 1,
            sep_char     => $opt_c,
            always_quote => 1, } );
    

For detailed control of the stacking of individual closing tokens the following controls can be used:

  -scp  or --stack-closing-paren
  -schb or --stack-closing-hash-brace
  -scsb or --stack-closing-square-bracket
    

The flag -sct is a synonym for -scp -schb -scsb.

-dnl, --delete-old-newlines

By default, perltidy first deletes all old line break locations, and then it looks for good break points to match the desired line length. Use -ndnl or --nodelete-old-newlines to force perltidy to retain all old line break points.

-anl, --add-newlines

By default, perltidy will add line breaks when necessary to create continuations of long lines and to improve the script appearance. Use -nanl or --noadd-newlines to prevent any new line breaks.

This flag does not prevent perltidy from eliminating existing line breaks; see --freeze-newlines to completely prevent changes to line break points.

Controlling whether perltidy breaks before or after operators

Four command line parameters provide some control over whether a line break should be before or after specific token types. Two parameters give detailed control:

-wba=s or --want-break-after=s, and

-wbb=s or --want-break-before=s.

These parameters are each followed by a quoted string, s, containing a list of token types (separated only by spaces). No more than one of each of these parameters should be specified, because repeating a command-line parameter always overwrites the previous one before perltidy ever sees it.

By default, perltidy breaks after these token types:
% + - * / x != == >= <= =~ !~ < > | &
= **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=

And perltidy breaks before these token types by default:
. << >> -> && || //

To illustrate, to cause a break after a concatenation operator, '.', rather than before it, the command line would be

  -wba="."
    

As another example, the following command would cause a break before math operators '+', '-', '/', and '*':

  -wbb="+ - / *"
    

These commands should work well for most of the token types that perltidy uses (use --dump-token-types for a list). Also try the -D flag on a short snippet of code and look at the .DEBUG file to see the tokenization. However, for a few token types there may be conflicts with hardwired logic which cause unexpected results. One example is curly braces, which should be controlled with the parameter bl provided for that purpose.

WARNING Be sure to put these tokens in quotes to avoid having them misinterpreted by your command shell.

Two additional parameters are available which, though they provide no further capability, can simplify input are:

-baao or --break-after-all-operators,

-bbao or --break-before-all-operators.

The -baao sets the default to be to break after all of the following operators:

    % + - * / x != == >= <= =~ !~ < > | & 
    = **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x=
    . : ? && || and or err xor
    

and the -bbao flag sets the default to break before all of these operators. These can be used to define an initial break preference which can be fine-tuned with the -wba and -wbb flags. For example, to break before all operators except an = one could use --bbao -wba='=' rather than listing every single perl operator except = on a -wbb flag.

Controlling List Formatting¶

Perltidy attempts to place comma-separated arrays of values in tables which look good. Its default algorithms usually work well, and they have been improving with each release, but several parameters are available to control list formatting.

-boc, --break-at-old-comma-breakpoints

This flag tells perltidy to try to break at all old commas. This is not the default. Normally, perltidy makes a best guess at list formatting, and seldom uses old comma breakpoints. Usually this works well, but consider:

    my @list = (1,
                1, 1,
                1, 2, 1,
                1, 3, 3, 1,
                1, 4, 6, 4, 1,);
    

The default formatting will flatten this down to one line:

    # perltidy (default)
    my @list = ( 1, 1, 1, 1, 2, 1, 1, 3, 3, 1, 1, 4, 6, 4, 1, );
    

which hides the structure. Using -boc, plus additional flags to retain the original style, yields

    # perltidy -boc -lp -pt=2 -vt=1 -vtc=1
    my @list = (1,
                1, 1,
                1, 2, 1,
                1, 3, 3, 1,
                1, 4, 6, 4, 1,);
    

A disadvantage of this flag is that all tables in the file must already be nicely formatted. For another possibility see the -fs flag in "Skipping Selected Sections of Code".

-mft=n, --maximum-fields-per-table=n

If the computed number of fields for any table exceeds n, then it will be reduced to n. The default value for n is a large number, 40. While this value should probably be left unchanged as a general rule, it might be used on a small section of code to force a list to have a particular number of fields per line, and then either the -boc flag could be used to retain this formatting, or a single comment could be introduced somewhere to freeze the formatting in future applications of perltidy.

    # perltidy -mft=2
    @month_of_year = (    
        'Jan', 'Feb',
        'Mar', 'Apr',
        'May', 'Jun',
        'Jul', 'Aug',
        'Sep', 'Oct',
        'Nov', 'Dec'
    );
    

-cab=n, --comma-arrow-breakpoints=n

A comma which follows a comma arrow, '=>', requires special consideration. In a long list, it is common to break at all such commas. This parameter can be used to control how perltidy breaks at these commas. (However, it will have no effect if old comma breaks are being forced because -boc is used). The possible values of n are:

 n=0 break at all commas after =>  
 n=1 stable: break at all commas after => unless this would break
     an existing one-line container (default)
 n=2 break at all commas after =>, but try to form the maximum
     maximum one-line container lengths
 n=3 do not treat commas after => specially at all
    

For example, given the following single line, perltidy by default will not add any line breaks because it would break the existing one-line container:

    bless { B => $B, Root => $Root } => $package;
    

Using -cab=0 will force a break after each comma-arrow item:

    # perltidy -cab=0:
    bless {
        B    => $B,
        Root => $Root
    } => $package;
    

If perltidy is subsequently run with this container broken, then by default it will break after each '=>' because the container is now broken. To reform a one-line container, the parameter -cab=2 would be needed.

The flag -cab=3 can be used to prevent these commas from being treated specially. In this case, an item such as "01" => 31 is treated as a single item in a table. The number of fields in this table will be determined by the same rules that are used for any other table. Here is an example.

    # perltidy -cab=3
    my %last_day = (
        "01" => 31, "02" => 29, "03" => 31, "04" => 30,
        "05" => 31, "06" => 30, "07" => 31, "08" => 31,
        "09" => 30, "10" => 31, "11" => 30, "12" => 31
    );
    

Retaining or Ignoring Existing Line Breaks¶

Several additional parameters are available for controlling the extent to which line breaks in the input script influence the output script. In most cases, the default parameter values are set so that, if a choice is possible, the output style follows the input style. For example, if a short logical container is broken in the input script, then the default behavior is for it to remain broken in the output script.

Most of the parameters in this section would only be required for a one-time conversion of a script from short container lengths to longer container lengths. The opposite effect, of converting long container lengths to shorter lengths, can be obtained by temporarily using a short maximum line length.

-bol, --break-at-old-logical-breakpoints

By default, if a logical expression is broken at a "&&", "||", "and", or "or", then the container will remain broken. Also, breaks at internal keywords "if" and "unless" will normally be retained. To prevent this, and thus form longer lines, use -nbol.

-bok, --break-at-old-keyword-breakpoints

By default, perltidy will retain a breakpoint before keywords which may return lists, such as "sort" and <map>. This allows chains of these operators to be displayed one per line. Use -nbok to prevent retaining these breakpoints.

-bot, --break-at-old-ternary-breakpoints

By default, if a conditional (ternary) operator is broken at a ":", then it will remain broken. To prevent this, and thereby form longer lines, use -nbot.

-iob, --ignore-old-breakpoints

Use this flag to tell perltidy to ignore existing line breaks to the maximum extent possible. This will tend to produce the longest possible containers, regardless of type, which do not exceed the line length limit.

-kis, --keep-interior-semicolons

Use the -kis flag to prevent breaking at a semicolon if there was no break there in the input file. Normally perltidy places a newline after each semicolon which terminates a statement unless several statements are contained within a one-line brace block. To illustrate, consider the following input lines:

    dbmclose(%verb_delim); undef %verb_delim;
    dbmclose(%expanded); undef %expanded;
    

The default is to break after each statement, giving

    dbmclose(%verb_delim);
    undef %verb_delim;
    dbmclose(%expanded);
    undef %expanded;
    

With perltidy -kis the multiple statements are retained:

    dbmclose(%verb_delim); undef %verb_delim;
    dbmclose(%expanded);   undef %expanded;
    

The statements are still subject to the specified value of maximum-line-length and will be broken if this maximum is exceeed.

Blank Line Control¶

Blank lines can improve the readability of a script if they are carefully placed. Perltidy has several commands for controlling the insertion, retention, and removal of blank lines.

-fbl, --freeze-blank-lines

Set -fbl if you want to the blank lines in your script to remain exactly as they are. The rest of the parameters in this section may then be ignored. (Note: setting the -fbl flag is equivalent to setting -mbl=0 and -kbl=2).

-bbc, --blanks-before-comments

A blank line will be introduced before a full-line comment. This is the default. Use -nbbc or --noblanks-before-comments to prevent such blank lines from being introduced.

-bbs, --blanks-before-subs

A blank line will be introduced before a sub definition, unless it is a one-liner or preceded by a comment. A blank line will also be introduced before a package statement and a BEGIN and END block. This is the default. The intention is to help display the structure of a program by setting off certain key sections of code. This is negated with -nbbs or --noblanks-before-subs.

-bbb, --blanks-before-blocks

A blank line will be introduced before blocks of coding delimited by for, foreach, while, until, and if, unless, in the following circumstances:

-lbl=n --long-block-line-count=n

This controls how often perltidy is allowed to add blank lines before certain block types (see previous section). The default is 8. Entering a value of 0 is equivalent to entering a very large number.

-mbl=n --maximum-consecutive-blank-lines=n

This parameter specifies the maximum number of consecutive blank lines which will be output within code sections of a script. The default is n=1. If the input file has more than n consecutive blank lines, the number will be reduced to n. If n=0 then no blank lines will be output (unless all old blank lines are retained with the -kbl=2 flag of the next section).

This flag obviously does not apply to pod sections, here-documents, and quotes.

-kbl=n, --keep-old-blank-lines=n

The -kbl=n flag gives you control over how your existing blank lines are treated.

The possible values of n are:

 n=0 ignore all old blank lines
 n=1 stable: keep old blanks, but limited by the value of the B<-mbl=n> flag
 n=2 keep all old blank lines, regardless of the value of the B<-mbl=n> flag
    

The default is n=1.

-sob, --swallow-optional-blank-lines

This is equivalent to kbl=0 and is included for compatability with previous versions.

-nsob, --noswallow-optional-blank-lines

This is equivalent to kbl=1 and is included for compatability with previous versions.

Styles¶

A style refers to a convenient collection of existing parameters.

-gnu, --gnu-style

-gnu gives an approximation to the GNU Coding Standards (which do not apply to perl) as they are sometimes implemented. At present, this style overrides the default style with the following parameters:

    -lp -bl -noll -pt=2 -bt=2 -sbt=2 -icp
    

-pbp, --perl-best-practices

-pbp is an abbreviation for the parameters in the book Perl Best Practices by Damian Conway:

    -l=78 -i=4 -ci=4 -st -se -vt=2 -cti=0 -pt=1 -bt=1 -sbt=1 -bbt=1 -nsfs -nolq
    -wbb="% + - * / x != == >= <= =~ !~ < > | & = 
          **= += *= &= <<= &&= -= /= |= >>= ||= //= .= %= ^= x="
    

Note that the -st and -se flags make perltidy act as a filter on one file only. These can be overridden with -nst and -nse if necessary.

Other Controls¶

Deleting selected text

Perltidy can selectively delete comments and/or pod documentation. The command -dac or --delete-all-comments will delete all comments and all pod documentation, leaving just code and any leading system control lines.

The command -dp or --delete-pod will remove all pod documentation (but not comments).

Two commands which remove comments (but not pod) are: -dbc or --delete-block-comments and -dsc or --delete-side-comments. (Hanging side comments will be deleted with block comments here.)

The negatives of these commands also work, and are the defaults. When block comments are deleted, any leading 'hash-bang' will be retained. Also, if the -x flag is used, any system commands before a leading hash-bang will be retained (even if they are in the form of comments).

Writing selected text to a file

When perltidy writes a formatted text file, it has the ability to also send selected text to a file with a .TEE extension. This text can include comments and pod documentation.

The command -tac or --tee-all-comments will write all comments and all pod documentation.

The command -tp or --tee-pod will write all pod documentation (but not comments).

The commands which write comments (but not pod) are: -tbc or --tee-block-comments and -tsc or --tee-side-comments. (Hanging side comments will be written with block comments here.)

The negatives of these commands also work, and are the defaults.

Using a .perltidyrc command file

If you use perltidy frequently, you probably won't be happy until you create a .perltidyrc file to avoid typing commonly-used parameters. Perltidy will first look in your current directory for a command file named .perltidyrc. If it does not find one, it will continue looking for one in other standard locations.

These other locations are system-dependent, and may be displayed with the command "perltidy -dpro". Under Unix systems, it will first look for an environment variable PERLTIDY. Then it will look for a .perltidyrc file in the home directory, and then for a system-wide file /usr/local/etc/perltidyrc, and then it will look for /etc/perltidyrc. Note that these last two system-wide files do not have a leading dot. Further system-dependent information will be found in the INSTALL file distributed with perltidy.

Under Windows, perltidy will also search for a configuration file named perltidy.ini since Windows does not allow files with a leading period (.). Use "perltidy -dpro" to see the possbile locations for your system. An example might be C:\Documents and Settings\All Users\perltidy.ini.

Another option is the use of the PERLTIDY environment variable. The method for setting environment variables depends upon the version of Windows that you are using. Instructions for Windows 95 and later versions can be found here:

http://www.netmanage.com/000/20021101_005_tcm21-6336.pdf

Under Windows NT / 2000 / XP the PERLTIDY environment variable can be placed in either the user section or the system section. The later makes the configuration file common to all users on the machine. Be sure to enter the full path of the configuration file in the value of the environment variable. Ex. PERLTIDY=C:\Documents and Settings\perltidy.ini

The configuation file is free format, and simply a list of parameters, just as they would be entered on a command line. Any number of lines may be used, with any number of parameters per line, although it may be easiest to read with one parameter per line. Blank lines are ignored, and text after a '#' is ignored to the end of a line.

Here is an example of a .perltidyrc file:

  # This is a simple of a .perltidyrc configuration file
  # This implements a highly spaced style
  -se    # errors to standard error output
  -w     # show all warnings
  -bl    # braces on new lines
  -pt=0  # parens not tight at all
  -bt=0  # braces not tight
  -sbt=0 # square brackets not tight
    

The parameters in the .perltidyrc file are installed first, so any parameters given on the command line will have priority over them.

To avoid confusion, perltidy ignores any command in the .perltidyrc file which would cause some kind of dump and an exit. These are:

 -h -v -ddf -dln -dop -dsn -dtt -dwls -dwrs -ss
    

There are several options may be helpful in debugging a .perltidyrc file:

Creating a new abbreviation

A special notation is available for use in a .perltidyrc file for creating an abbreviation for a group of options. This can be used to create a shorthand for one or more styles which are frequently, but not always, used. The notation is to group the options within curly braces which are preceded by the name of the alias (without leading dashes), like this:

        newword {
        -opt1
        -opt2
        }
    

where newword is the abbreviation, and opt1, etc, are existing parameters or other abbreviations. The main syntax requirement is that the new abbreviation must begin on a new line. Space before and after the curly braces is optional. For a specific example, the following line

        airy {-bl -pt=0 -bt=0 -sbt=0}
    

could be placed in a .perltidyrc file, and then invoked at will with

        perltidy -airy somefile.pl
    

(Either "-airy" or "--airy" may be used).

Skipping leading non-perl commands with -x or --look-for-hash-bang

If your script has leading lines of system commands or other text which are not valid perl code, and which are separated from the start of the perl code by a "hash-bang" line, ( a line of the form "#!...perl" ), you must use the -x flag to tell perltidy not to parse and format any lines before the "hash-bang" line. This option also invokes perl with a -x flag when checking the syntax. This option was originally added to allow perltidy to parse interactive VMS scripts, but it should be used for any script which is normally invoked with "perl -x".

Making a file unreadable

The goal of perltidy is to improve the readability of files, but there are two commands which have the opposite effect, --mangle and --extrude. They are actually merely aliases for combinations of other parameters. Both of these strip all possible whitespace, but leave comments and pod documents, so that they are essentially reversible. The difference between these is that --mangle puts the fewest possible line breaks in a script while --extrude puts the maximum possible. Note that these options do not provided any meaningful obfuscation, because perltidy can be used to reformat the files. They were originally developed to help test the tokenization logic of perltidy, but they have other uses. One use for --mangle is the following:

  perltidy --mangle myfile.pl -st | perltidy -o myfile.pl.new
    

This will form the maximum possible number of one-line blocks (see next section), and can sometimes help clean up a badly formatted script.

A similar technique can be used with --extrude instead of --mangle to make the minimum number of one-line blocks.

Another use for --mangle is to combine it with -dac to reduce the file size of a perl script.

One-line blocks

There are a few points to note regarding one-line blocks. A one-line block is something like this,

        if ($x > 0) { $y = 1 / $x }
    

where the contents within the curly braces is short enough to fit on a single line.

With few exceptions, perltidy retains existing one-line blocks, if it is possible within the line-length constraint, but it does not attempt to form new ones. In other words, perltidy will try to follow the one-line block style of the input file.

If an existing one-line block is longer than the maximum line length, however, it will be broken into multiple lines. When this happens, perltidy checks for and adds any optional terminating semicolon (unless the -nasc option is used) if the block is a code block.

The main exception is that perltidy will attempt to form new one-line blocks following the keywords "map", "eval", and "sort", because these code blocks are often small and most clearly displayed in a single line.

One-line block rules can conflict with the cuddled-else option. When the cuddled-else option is used, perltidy retains existing one-line blocks, even if they do not obey cuddled-else formatting.

Occasionally, when one-line blocks get broken because they exceed the available line length, the formatting will violate the requested brace style. If this happens, reformatting the script a second time should correct the problem.

Debugging

The following flags are available for debugging:

--dump-defaults or -ddf will write the default option set to standard output and quit

--dump-profile or -dpro will write the name of the current configuration file and its contents to standard output and quit.

--dump-options or -dop will write current option set to standard output and quit.

--dump-long-names or -dln will write all command line long names (passed to Get_options) to standard output and quit.

--dump-short-names or -dsn will write all command line short names to standard output and quit.

--dump-token-types or -dtt will write a list of all token types to standard output and quit.

--dump-want-left-space or -dwls will write the hash %want_left_space to standard output and quit. See the section on controlling whitespace around tokens.

--dump-want-right-space or -dwrs will write the hash %want_right_space to standard output and quit. See the section on controlling whitespace around tokens.

-DEBUG will write a file with extension .DEBUG for each input file showing the tokenization of all lines of code.

Working with MakeMaker, AutoLoader and SelfLoader

The first $VERSION line of a file which might be eval'd by MakeMaker is passed through unchanged except for indentation. Use --nopass-version-line, or -npvl, to deactivate this feature.

If the AutoLoader module is used, perltidy will continue formatting code after seeing an __END__ line. Use --nolook-for-autoloader, or -nlal, to deactivate this feature.

Likewise, if the SelfLoader module is used, perltidy will continue formatting code after seeing a __DATA__ line. Use --nolook-for-selfloader, or -nlsl, to deactivate this feature.

Working around problems with older version of Perl

Perltidy contains a number of rules which help avoid known subtleties and problems with older versions of perl, and these rules always take priority over whatever formatting flags have been set. For example, perltidy will usually avoid starting a new line with a bareword, because this might cause problems if "use strict" is active.

There is no way to override these rules.

Specifying Block Types¶

Several parameters which refer to code block types may be customized by also specifying an associated list of block types. The type of a block is the name of the keyword which introduces that block, such as if, else, or sub. An exception is a labeled block, which has no keyword, and should be specified with just a colon.

For example, the following parameter specifies "sub", labels, "BEGIN", and "END" blocks:

   -cscl="sub : BEGIN END"

(the meaning of the -cscl parameter is described above.) Note that quotes are required around the list of block types because of the spaces.

Specifying File Extensions¶

Several parameters allow default file extensions to be overridden. For example, a backup file extension may be specified with -bext=ext, where ext is some new extension. In order to provides the user some flexibility, the following convention is used in all cases to decide if a leading '.' should be used. If the extension "ext" begins with "A-Z", "a-z", or "0-9", then it will be appended to the filename with an intermediate '.' (or perhaps an '_' on VMS systems). Otherwise, it will be appended directly.

For example, suppose the file is somefile.pl. For "-bext=old", a '.' is added to give somefile.pl.old. For "-bext=.old", no additional '.' is added, so again the backup file is somefile.pl.old. For "-bext=~", then no dot is added, and the backup file will be somefile.pl~ .