On: Easily handle CLI operation via Python instead of regular Bash programs

[js2]

Perl too. The -p, -n, -e switches work identically.

-n causes Perl to assume the following loop around your program, which makes it iterate over filename arguments somewhat like sed -n or awk:

    LINE:
      while (<>) {
          ...             # your program goes here
      }

-p causes Perl to assume the following loop around your program, which makes it iterate over filename arguments somewhat like sed:

    LINE:
      while (<>) {
          ...             # your program goes here
      } continue {
          print or die "-p destination: $!\n";
      }

https://linux.die.net/man/1/perlrun

[p_l → js2]

Little underappreciated part of Ruby these days is that part of it grew out of Perl, and specifically supports similar kind of scripting for daily tasks. Pretty sure both thsoe specific switches and some of the sigils used in syntax came from this Perl legacy.

[rcthompson → js2]

My mnemonic for the perl switches is "perl dash lane", i.e. `perl -lane`. And then I remember to replace "n" with "p" if I want to auto-print every line after munging it. I mainly use this as a replacement for sed/awk/grep because PCRE syntax is more familiar to me than whatever flavor(s) of regexes are used by those tools.

[freedomben → js2]

Yes thanks, I should have added that perl took it (and improved it) from awk, and ruby took it from perl. Most ruby people don't like to remember that ruby has a lot of perl-isms in it, but I think perl was a great language (and probably is, though I liked ruby so much better I never looked back).