Without other narrates, this note is only intended for Debian or Ubuntu.
command | function | usage |
---|---|---|
update-alternatives | multi-version runnable program preference management | |
test -x ${file} | test if ${file} exists and granted with executable permission | |
if [ -f ${file} ] | test if this file is a regular file | |
set -e | cause the shell to exit if any subcommand or pipeline returns a non-zero status |