perl

The Perl 5 language interpreter

TLDR

Run a Perl script

$ perl [script.pl]

Execute a one-liner

$ perl -e 'print "Hello\n"'

In-place edit a file with substitution

$ perl -i -pe 's/old/new/g' [file]

In-place edit with backup (original saved as .bak)

$ perl -i.bak -pe 's/old/new/g' [file]

Print specific columns with autosplit

$ perl -ane 'print "$F[0]\n"' [file]

Check syntax without running

$ perl -c [script.pl]

Process input line by line (like sed/awk)

$ perl -ne 'print if /[pattern]/' [file]

Use a module from the command line

$ perl -MJSON -e 'print encode_json({key => "value"})'

SYNOPSIS

perl [options] [program] [arguments]

perl is the Perl 5 language interpreter. Perl is a general-purpose programming language originally developed for text manipulation, combining features from C, sed, awk, and shell scripting.The language excels at text processing with powerful built-in regular expression support. It is widely used for system administration, web development, network programming, and data processing. The Comprehensive Perl Archive Network (CPAN) provides a vast repository of reusable modules.

PARAMETERS

PROGRAM

Perl script file to execute.

-e CODE

Execute the given code as a one-liner. Multiple -e flags are allowed.

-E CODE

Like -e but enables all optional features (say, state, etc.).

-n

Wrap code in a while(<>) loop, reading input line by line without printing.

-p

Like -n but also prints $_ after each iteration.

-i[EXT]

In-place edit files. If extension given, creates backup with that suffix.

-a

Turn on autosplit mode (used with -n or -p). Splits each line into @F.

-F PATTERN

Specify the split pattern for autosplit mode (default: whitespace).

-l

Enable automatic line-ending processing. Strips newlines on input, adds on output.

-0[OCTAL]

Specify input record separator as octal value. -0777 slurps entire files.

-w

Enable warnings (prefer `use warnings;` in scripts).

-W

Enable all warnings unconditionally.

-c

Syntax check only; do not execute the program.

-MMODULE

Load a module before executing (equivalent to `use MODULE`).

-T

Enable taint mode for security. Untrusted data cannot affect the system.

-S

Use PATH to find the script. Emulates #! on platforms that don't support it.

-d

Run the program under the debugger.

-v

Print version and configuration summary.

CAVEATS

Modern Perl scripts should use `use strict;` and `use warnings;` for safer code. The -i flag without an extension modifies files in place with no backup. CPAN modules can be installed with the cpan command.

HISTORY

Perl was created by Larry Wall in 1987 as a practical language for text manipulation and report generation. Perl 5, released in 1994, introduced major features including references, objects, and modules.