Checking if a program is installed

[cjoshmartin]

command -v foo >/dev/null 2>&1 || { echo "I require foo but it's not installed. Aborting." >&2; exit 1; }

[cjoshmartin]

https://stackoverflow.com/questions/592620/check-if-a-program-exists-from-a-bash-script

[cjoshmartin]

checking if a folder exist: https://stackoverflow.com/questions/59838/check-if-a-directory-exists-in-a-shell-script