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, Jan 02 '15 at 15:07
Yo *do* know about the [`chmod`](http://man7.org/linux/man-pages/man1/chmod.1.html) command? — Some programmer dude, Jan 02 '15 at 15:08
Yes I know to use chmod +x file_name but I don't know how to implement it in the script :( — Selendi, Jan 02 '15 at 15:09

SMA · Answer 1 · 2015-01-02T15:09:48.207

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 02 '15 at 15:09

answered Jan 02 '15 at 15:09

SMA

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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 Jan 02 '15 at 15:13
Or viceversa ./exist.sh -x file_name – Selendi Jan 02 '15 at 15:13
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. – SMA Jan 02 '15 at 15:16

score 1 · Accepted Answer · edited May 23 '17 at 12:12

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

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. — Etan Reisner, Jan 02 '15 at 16:37

Bash script with argument that makes file executable

2 Answers2