core unix

basic file stuff

touch - create file
mkdir - create directory
cp - copy
mv - move
rm - delete
ln - create symlink
ls - list directory

how big is it
wc - word count
du - file size in bytes
df - filesystem usage

slice & dice files
sed - replace regex
tr - replace character
grep - search file
cut - get column
awk - get column ( more)
sort - sort lines
uniq - unique lines
head - first 10 lines
tail - last 10 lines

filesystems
mount - mount a filesystem
umount - unmount
dd - copy data to a disk

manage processes
ps - list processes
lsof - list open files
kill - send a signal
pkill - fancy `kill`
top - who's using CPU?
uptime - time since reboot

permissions
chown - change owner
chmod - change permissions


time stuff
time - measure runtime
date - current time
sleep - wait X seconds
cal - cute calendar


useful with pipes
less - scroll text
cat - print file contents
tee - stdin -> file stdout
xargs - run cmd for each line


compression
tar - make/extract tar files
gzip - compress with gzip
gunzip - decompress
zip - compress with zip
unzip - decompress


& more
which - find cmd on PATH
man - read man page
crontab - edit crontab
md5sum - calculate md5sum
diff - diff files


shell builtins (not programs)

export - set env var
alias - create an alias
source - eval code from file
cd - change directory
type - is cmd a builtin?
history - view history
echo - print text
printf - like C printf
disown - TODO