cheat.sheets/sheets/perl

# perl
# The Perl 5 language interpreter.

# Parse and execute a Perl script:
perl script.pl

# Check syntax errors on a Perl script:
perl -c script.pl

# Parse and execute a perl statement:
perl -e perl_statement

# Import module before execution of a perl statement:
perl -Mmodule -e perl_statement

# Run a Perl script in debug mode, using perldebug:
perl -d script.pl

# Loo[p] over all lines of a file, editing them [i]n-place using a find/replace [e]xpression:
perl -p -i -e 's/find/replace/g' filename

# Run a find/replace expression on a file, saving the original file with a given extension:
perl -p -i'.old' -e 's/find/replace/g' filename

# See also:
#   Perl language cheat sheets at /perl/
#   list of pages:      /perl/:list
#   learn perl:         /perl/:learn
#   perl one-liners:    /perl/1line
#   search in pages:    /perl/~keyword

# Perl method of listing out the environment variables, sans values.
perl -e 'print("$_\n") foreach keys(%ENV)'