Some bash stuff

expand aliases: shopt -s expand_aliases
exit on fail: set -e (upon a command exiting with a non-zero status)
trap the exit signal: trap 'rm -f foo' EXIT (e.g. to perform cleanup upon exit)
while IFS=',' read -r var_name; do
echo test`which sh`

awk

awk ‑F: 'OFS="-" { print $1 $3 $NF }' /etc/passwd

fortune | awk '{ print toupper($0) }'

awk '$1 ~ foo { print $3 }'

comparison operators: ==, !=, <, <=, (etc), ~ (match, e.g. contain), !~ (not match)
$NF - last field