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How can I check if a directory exists in a Bash shell script?


Question

What command can be used to check if a directory exists or not, within a Bash shell script?

2020/05/07
1
3787
5/7/2020 11:52:47 AM

Accepted Answer

To check if a directory exists in a shell script, you can use the following:

if [ -d "$DIRECTORY" ]; then
  # Control will enter here if $DIRECTORY exists.
fi

Or to check if a directory doesn't exist:

if [ ! -d "$DIRECTORY" ]; then
  # Control will enter here if $DIRECTORY doesn't exist.
fi

However, as Jon Ericson points out, subsequent commands may not work as intended if you do not take into account that a symbolic link to a directory will also pass this check. E.g. running this:

ln -s "$ACTUAL_DIR" "$SYMLINK"
if [ -d "$SYMLINK" ]; then 
  rmdir "$SYMLINK" 
fi

Will produce the error message:

rmdir: failed to remove `symlink': Not a directory

So symbolic links may have to be treated differently, if subsequent commands expect directories:

if [ -d "$LINK_OR_DIR" ]; then 
  if [ -L "$LINK_OR_DIR" ]; then
    # It is a symlink!
    # Symbolic link specific commands go here.
    rm "$LINK_OR_DIR"
  else
    # It's a directory!
    # Directory command goes here.
    rmdir "$LINK_OR_DIR"
  fi
fi

Take particular note of the double-quotes used to wrap the variables. The reason for this is explained by 8jean in another answer.

If the variables contain spaces or other unusual characters it will probably cause the script to fail.

2020/05/07
5231
5/7/2020 11:54:34 AM

Remember to always wrap variables in double quotes when referencing them in a Bash script. Kids these days grow up with the idea that they can have spaces and lots of other funny characters in their directory names. (Spaces! Back in my days, we didn't have no fancy spaces! ;))

One day, one of those kids will run your script with $DIRECTORY set to "My M0viez" and your script will blow up. You don't want that. So use this.

if [ -d "$DIRECTORY" ]; then
    # Will enter here if $DIRECTORY exists, even if it contains spaces
fi
2020/05/07

Note the -d test can produce some surprising results:

$ ln -s tmp/ t
$ if [ -d t ]; then rmdir t; fi
rmdir: directory "t": Path component not a directory

File under: "When is a directory not a directory?" The answer: "When it's a symlink to a directory." A slightly more thorough test:

if [ -d t ]; then 
   if [ -L t ]; then 
      rm t
   else 
      rmdir t
   fi
fi

You can find more information in the Bash manual on Bash conditional expressions and the [ builtin command and the [[ compound commmand.

2017/09/11

I find the double-bracket version of test makes writing logic tests more natural:

if [[ -d "${DIRECTORY}" && ! -L "${DIRECTORY}" ]] ; then
    echo "It's a bona-fide directory"
fi
2013/07/01

Shorter form:

[ -d "$DIR" ] && echo "Yes"
2015/05/25

To check if a directory exists you can use a simple if structure like this:

if [ -d directory/path to a directory ] ; then
# Things to do

else #if needed #also: elif [new condition]
# Things to do
fi

You can also do it in the negative:

if [ ! -d directory/path to a directory ] ; then
# Things to do when not an existing directory

Note: Be careful. Leave empty spaces on either side of both opening and closing braces.

With the same syntax you can use:

-e: any kind of archive

-f: file

-h: symbolic link

-r: readable file

-w: writable file

-x: executable file

-s: file size greater than zero
2020/05/07

Source: https://stackoverflow.com/questions/59838
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