bash determine if variable is empty and if so exit.
The answer I prefer is following
[[ -z "$1" ]] && { echo "Parameter 1 is empty" ; exit 1; }Note, don't forget the ; into the {} after each instruction
One way to check if a variable is empty is:
if [ "$var" = "" ]; then # $var is emptyfiAnother, shorter alternative is this:
[ "$var" ] || # var is empty
In bash you can use set -u which causes bash to exit on failed parameter expansion.
From bash man (section about set builtin):
-u
Treat unset variables and parameters other than the special parameters "@" and "*" as an error when performing parameter expansion. If expansion is attempted on an unset variable or parameter, the shell prints an error message, and, if not interactive, exits with a non-zero status.
For more information I recommend this article: http://redsymbol.net/articles/unofficial-bash-strict-mode/