Perl one-liners

Some tasks can be conveniently achieved with Perl one-liners. Perl is a scripting language originating in the environment of another operating system. Since many Windows computing environments have Perl installed, Perl one-liners are a natural and compact extension of Windows batch scripting.

Examples:

• echo "abcbbc"| perl -pe "s/a.*?c/ac/"
  • Lets Perl act as sed, the utility that supports textual replacements specified using regular expressions.
• echo a b| perl -lane "print $F[1]"
  • Lets Perl act as cut command, displaying the 2nd field or column of the line, in this case b. Use $F[2] to display 3rd field; indexing starts at zero. Native solution: FOR /f.
• perl -ne "print if /\x22hello\x22/" file.txt
  • Acts as grep or FINDSTR, outputting the lines in file.txt that match the regular expression after if. Uses the powerful Perl regular expressions, more powerful than those of FINDSTR.
• perl -ne "$. <= 10 and print" MyFile.txt
  • Lets Perl act as head -10 command, outputting the first 10 lines of the file.
• perl -e "sleep 5"
  • Waits for 5 seconds.
• for /f %i in ('perl -MPOSIX -le "print strftime '%Y-%m-%d', localtime"') do @set isodate=%i
  • Gets current date in the ISO format into isodate variable.
• perl -MWin32::Clipboard -e "print Win32::Clipboard->Get()"
  • Outputs the text content of the clipboard. When stored to getclip.bat, yields a handy getclip command to complement CLIP command.
• perl -MText::Diff -e "print diff 'File1.txt', 'File2.txt'"
  • Outputs differences between two files in a format similar to diff command known from other operating systems, including context lines, lines starting with + and lines starting with -.

On the web, Perl one-liners are often posted in the command-line conventions of another operating system, including the use of apostrophe (') to surround the arguments instead of Windows quotation marks. These need to be tweaked for Windows.

Links:

• Perl One-Liners by Peteris Krumins at github.com
• Why doesn't my Perl one-liner work on Windows? at stackoverflow.com
• W:One-liner program#Perl