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Perl as a command line utility

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Question

How to replace sed and awk with Perl in command line / shell scripts?

Examples

$ perl -e 'print "Hello, World!\n"'
Hello, World!

The -e option (execute) instructs the Perl interpreter that the next argument is a Perl statement to be compiled and run. If -e is given, Perl will not look for a script filename in the argument list. Multiple -e commands may be given to build up a multi-line script.

$ echo laci | perl -ne 'if (/a/) { s#a#A#; print; }'
lAci

$ echo hello | perl -ne  "s/h/H/; print;"
Hello

$ echo hello | perl -pne  "s/h/H/"
Hello

The option -p prints lines.

$ echo file.ext | perl -npe  "s|\.(.*)$||"
file

Remove file extension. Note: don't use s###; the character '#' will cause problems.

jabba@hoth:~$ FILE=file.ext
jabba@hoth:~$ echo $FILE
file.ext
jabba@hoth:~$ FILE=`echo $FILE | perl -npe  "s|\.(.*)$||"`
jabba@hoth:~$ echo $FILE
file

Manipulate shell variables (as strings) with Perl in command line.

More examples

• http://www.softpanorama.org/Scripting/Perlorama/perl_in_command_line.shtml
• http://www.softpanorama.org/Scripting/Perlorama/perl_one_liners.shtml