These are some unix shell (bash/ksh/tcsh/...) tricks I've collected. I'm placing them here because, typically I'm away from my personal machine when I most need one.

Last Workday/Weekday of the Month (see here)

cal | awk '{print $2,$3,$4,$5,$6}' | tr -s '[:blank:]' '\n' | tail -1

Yesterday in Perl

perl -e '@T=localtime(time-86400);printf("%2d/%2d/%4d\n",$T[4]+1,$T[3],$T[5]+1900)'
perl -e 'use POSIX;print POSIX::strftime("%m/$d/%Y\n",localtime(time-86400))'

Fast Process Search (fps) - I'm constantly checking to see if a certain program or process is running. This helps reduce the typing and the clutter.

    function fps {
        (( $# )) &&
        ps -aux | sed -n "1p;/_µµµµ_µµµµ_fps_µµµµ_µµµµ_/d;/$1/p" ||
        echo "Usage: fps <search string>"
    }

List All Available Man Pages:

man --path | perl -pe 's/:/\n/g' | xargs -J% -n1 find % -type f | xargs basename | sort -u

Dos2Unix Line Ending Conversion:

perl -pi -e 's/\r\n/\n/;' filename ...

Subtract Files: Output all lines in FileA not also in FileB

sort FileA | uniq | sort - FileB FileB | uniq -u

If you know that FileA contains unique lines only, then this simplifies to:

sort FileA FileB FileB | uniq -u