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 $d
done
)
and this works just fine unless there are spaces in the command line arguments (even if those arguments are quoted). For example, calling the script like this: test.sh "Cherry Hill" "New York City"
produces the following output:
Cherry Hill New York City
First, don't do it that way. The best approach is to use find -exec
properly:
# this is safe
find test -type d -exec echo '{}' +
The other safe approach is to use NUL-terminated list, though this requires that your find support -print0
:
# this is safe
while IFS= read -r -d '' n; do
printf '%q\n' "$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