Top Unix Command Line Utilities

joe, ls, cd, time, cdbdump, tail, more, cat, rm, grep, wc, apachectl restart, find, curl, chmod, history, mv, locate, cpan, apt-get, pwd

But the most useful one is a command line Perl utility I called "flt" that executes a block of perl code for each in the stdin.

cat file.txt | flt ' $line=~ s|\s+| |gsi; print $line."\n"; '

That would compact free spaces

find . | flt ' if (-f $line) { print (-s $line)."\n"; } '

This would print the size of all files in the current folder and subfolders.

So it works like awk, but with full Perl, no need to learn awk syntax. You can do conditionals, loops and whatnot. I write 30% of my one time throw away scripts directly in the command line.

http://perldoc.perl.org/perlrun.html#*-n*

Those "flt" lines could be written

  perl -lpe 's|\s+| |gsi' file.txt
  find . | perl -ne 'if (-f) { print -s }'

Of course, "perl -ne" is longer than "flt", and I appreciate all this implicit use of $_ is not to everyone's tastes.