add ok function to exit with a generic error message after a previous call went wring

bsf.sh

@@ -12,6 +12,10 @@ sayn ()   { printf %s "$*" ; }
 ## check if user is root
 root ()   { [[ "$EUID" -eq 0 ]] ; }
 
+## check if last call had errors
+## if yes print generic error message and exit
+ok() { [[ "$?" -ne 0 ]] && echo "ERROR, aborting." && exit 1; }
+
 ## colors
 # use ANSI escape codes
 normal () { printf '\033[0m'    ; }