Question

I have a bash shell script that loops through all child directories (but not files) of a certain directory. The problem is that some of the directory names contain spaces.

Here are the contents of my test directory:

$ls -F test Baltimore/  Cherry Hill/  Edison/  New York City/  Philadelphia/  cities.txt 

And the code that loops through the directories:

for f in `find test/* -type d`; do   echo $f done 

Here’s the output:

 test/Baltimore test/Cherry Hill test/Edison  test/New York City test/Philadelphia 

Cherry Hill and New York City are treated as 2 or 3 separate entries.

I tried quoting the filenames, like so:

for f in `find test/* -type d | sed -e 's/^/\'/' | sed -e 's/$/\'/'`; do   echo $f done 

but to no avail.

There’s got to be a simple way to do this.

---

The answers below are great. But to make this more complicated – I don’t always want to use the directories listed in my test directory. Sometimes I want to pass in the directory names as command-line parameters instead.

I took Charles’ suggestion of setting the IFS and came up with the following:

dirlist='${@}' (   [[ -z '$dirlist' ]] && dirlist=`find test -mindepth 1 -type d` && IFS=$'\n'   for d in $dirlist; do     echo $d   done ) 

and this works just fine unless there are spaces in the command line arguments (even if those arguments are quoted). For example, calling the script like this: test.sh 'Cherry Hill' 'New York City' produces the following output:

 Cherry Hill New York City 

Answer 1

First, don’t do it that way. The best approach is to use find -exec properly:

# this is safe find test -type d -exec echo '{}' + 

The other safe approach is to use NUL-terminated list, though this requires that your find support -print0:

# this is safe while IFS= read -r -d '' n; do   printf '%q\n' '$n' done < <(find test -mindepth 1 -type d -print0) 

You can also populate an array from find, and pass that array later:

# this is safe declare -a myarray while IFS= read -r -d '' n; do   myarray+=( '$n' ) done < <(find test -mindepth 1 -type d -print0) printf '%q\n' '${myarray[@]}' # printf is an example; use it however you want 

If your find doesn’t support -print0, your result is then unsafe — the below will not behave as desired if files exist containing newlines in their names (which, yes, is legal):

# this is unsafe while IFS= read -r n; do   printf '%q\n' '$n' done < <(find test -mindepth 1 -type d) 

If one isn’t going to use one of the above, a third approach (less efficient in terms of both time and memory usage, as it reads the entire output of the subprocess before doing word-splitting) is to use an IFS variable which doesn’t contain the space character. Turn off globbing (set -f) to prevent strings containing glob characters such as [], * or ? from being expanded:

# this is unsafe (but less unsafe than it would be without the following precautions) (  IFS=$'\n' # split only on newlines  set -f    # disable globbing  for n in $(find test -mindepth 1 -type d); do    printf '%q\n' '$n'  done ) 

Finally, for the command-line parameter case, you should be using arrays if your shell supports them (i.e. it’s ksh, bash or zsh):

# this is safe for d in '$@'; do   printf '%s\n' '$d' done 

will maintain separation. Note that the quoting (and the use of $@ rather than $*) is important. Arrays can be populated in other ways as well, such as glob expressions:

# this is safe entries=( test/* ) for d in '${entries[@]}'; do   printf '%s\n' '$d' done