Bash script with argument that makes file executable

Question

I need to make a bash script that checks if the file or directory exists,then if the file does,it checks the executable permission.I need to modify the script to be able to give a file executable permissions from an argument.

Example: Console input ./exist.sh +x file_name should make the file executable.

This is the unfinished code that checks if the file/directory exists and if the file is executable or not. I need to add the chmod argument part.

#!/bin/bash
file=$1
if [ -x $file ]; then
    echo "The file '$file' exists and it is exxecutable"

else
    echo "The file '$file' is not executable (or does not exist)"

fi

if [ -d $file ]; then
    echo "There is a directory named '$file'"

else
    echo "There is no directory named '$file'"

fi

It just checks if the file is executable. I need it to be able to change the permission. — Selendi
– Selendi, Commented Jan 2, 2015 at 15:07
Yes I know to use chmod +x file_name but I don't know how to implement it in the script :( — Selendi
– Selendi, Commented Jan 2, 2015 at 15:09

Community · Accepted Answer · 2017-05-23 12:12:49Z

1

If you have optional arguments to your script, you need to check for them first.

In the case of just a couple of simple arguments, it would be simpler to check for them explicitly.

MAKEEXECUTABLE=0
while [ "${1:0:1}" = "+" ]; do
  case $1 in
     "+x")
         MAKEEXECUTABLE=1
        shift
        ;;
     *)
        echo "Unknown option '$1'"
        exit
   esac
done
file=$1

Then after you have determined that the file is not executable

if [ $MAKEEXECUTABLE -eq 1 ]; then
   chmod +x $file
fi

Should you decide to add more complex options, you may want to use something like getops:example of how to use getopts in bash

edited May 23, 2017 at 12:12

CommunityBot

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answered Jan 2, 2015 at 15:26

Joe

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1 Comment

Etan Reisner Over a year ago

Or just use $1 as the argument to chmod directly if it is the change you want to make to the file and you've asserted that it is a safe/correct mode already.

SMA · Accepted Answer · 2015-01-02 15:09:48Z

1

Add chmod something like:

if [ ! -x "$file" ]; then
   chmod +x $file
fi

This means if file does not have execute persmission, then add execute permission for the user.

edited Jan 2, 2015 at 15:09

answered Jan 2, 2015 at 15:09

SMA

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3 Comments

Selendi Over a year ago

Yes I know. But I am supposed to give the chmod permission from the terminal when executing the script. Ex: ./exist.sh +x file_name

Selendi Over a year ago

Or viceversa ./exist.sh -x file_name

SMA Over a year ago

Then try: chmod +x file_name; ./exist.sh .. by writing -x after ./exist.sh you are trying to pass parameter to shell script and its not going to change the permission of your script.

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