How to create a flag with getopts to run a command

问题

I need help with my getopts, i want to be able to run this command ( mount command) only if i pass a flag ( -d in this case). below output is what i have on my script but it doesn't seem to work.

CHECKMOUNT=" "

while getopts ":d" opt
do
  case "$opt" in

  d) CHECKMOUNT="true" ;;

      usage >&2
      exit 1;;
    esac
   done
  shift `expr $OPTIND-1`

FS_TO_CHECK="/dev" 

if [ "$CHECKMOUNT" = "true" ] 
then
  if cat /proc/mounts | grep $FS_TO_CHECK > /dev/null; then
   # Filesystem is mounted
else
   # Filesystem is not mounted
  fi
fi

回答1:

Your script has a number of problems.

Here is the minimal list of fixes to get it working:

While is not a bash control statement, it's while. Case is important.
Whitespace is important: if ["$CHECKMOUNT"= "true"] doesn't work and should cause error messages. You need spaces around the brackets and around the =, like so: if [ "$CHECKMOUNT" = "true" ].
Your usage of getopts is incorrect, I'm guessing that you mistyped this copying an example: While getopts :d: opt should be: while getopts ":d" opt.
Your usage of shift is incorrect. This should cause error messages. Change this to: shift $((OPTIND-1)) if you need to shift OPTIND.
The bare text unknocn flag seems like a comment, precede it with #, otherwise you'll get an error when using an unknown option.
There is no usage function. Define one, or change usage in your \?) case to an echo with usage instructions.

Finally, if your script only requires a single optional argument, you might also simply process it yourself instead of using getopt - the first argument to your script is stored in the special variable $1:

if [ "$1" = "-d" ]; then
    CHECKMOUNT="true"
elif [ "$1" != "" ]; then
    usage >&2
    exit 1
fi

来源：https://stackoverflow.com/questions/11659981/how-to-create-a-flag-with-getopts-to-run-a-command

标签

bash

shell

getopts