Bash
random by max number of case
$ echo ${RANDOM:0:3}
substitution
- remove dirname
f="./4-Attya-anatomie/expose.pdf"
echo ${f##*/}
expose.pdf
- extension
file=ra.pdf
echo "${file:0:-4}"
ra
$ f="/etc/resolv.conf"
$ echo "${f#/etc/}"
resolv.conf
- not determiner fisrt match
$ f="/etc/resolv.conf"
$ echo "${f#*/}"
resolv.conf
interpreted var : eval it
hello=2020
var="hello"
echo ${!var}
# 2020
format string like a table
- select words
- add spaces
- trim spaces: by accept only
14char
sed 's/\(\(\w\|+\| \)\{14\}\) */\1'