Checking for the existence of multiple directories

Question

I want to check for the existence of multiple directories, say, dir1, dir2 and dir3, in the working directory.

I have the following

if [ -d "$PWD/dir1" ] && [ -d "$PWD/dir2" ] && [ -d "$PWD/dir3" ]; then
    echo True
else
    echo False
fi

But I suspect there is a more elegant way of doing this. Do not assume that there is a pattern in the names of the directories.

The goal is to check for the existence of a few directories and for the nonexistence of others.

I'm using Bash, but portable code is preferred.

Answer 1

I would loop:

result=True
for dir in \
        "$PWD/dir1" \
        "$PWD/dir2" \
        "$PWD/dir3" 
do
    if ! [ -d "$dir" ]; then
        result=False
        break
    fi
done
echo "$result"

The break causes the loop to short-circuit, just like your chain of &&

Answer 2

If you already expect them to be directories and are just checking whether they all exist, you could use the exit code from the ls utility to determine whether one or more "errors occurred":

ls "$PWD/dir1" "$PWD/dir2" "$PWD/dir3" >/dev/null 2>&1 && echo All there

I redirect the output and stderr to /dev/null in order to make it disappear, since we only care about the exit code from ls, not its output. Anything that's written to /dev/null disappears — it is not written to your terminal.

Answer 3

A loop might be more elegant:

arr=("$PWD/dir1" "$PWD/dir2" "$PWD/dir2")
for d in "${arr[@]}"; do
    if [ -d "$d"]; then
        echo True
    else
        echo False
    fi
done

This is Bash. A more portable one is Sh. There you can use the positional array:

set -- "$PWD/dir1" "$PWD/dir2" "$PWD/dir2"

Then to loop over it use "$@".

Answer 4

Why not just:

if [ -d "dir1" -a -d "dir2" -a -d "dir3" ]; then
    echo True
else
    echo False
fi

Answer 5

As per the question, two portable shell functions that test for the existence and nonexistence of multiple directories:

# Returns success if all given arguments exists and are directories.
ck_dir_exists () {
    for dir do
        [ -d "$dir" ] || return 1
    done
}

# Returns success if none of the given arguments are existing directories.
ck_dir_notexists () {
    for dir do
        [ ! -d "$dir" ] || return 1
    done
}

Example:

$ mkdir dir1 dir2

$ ck_dir_exists dir1 dir2; echo $?
0
$ ck_dir_exists dir1 dir2 dir3; echo $?
1

$ ck_dir_notexists dir1 dir2 dir3; echo $?
1
$ ck_dir_notexists dir3 dir4; echo $?
0

Answer 6

The goal is to check for the existence of a few directories and for the nonexistence of others.  _{[Emphasis added]}

Building on glenn jackman’s answer, we can test for the nonexistence of other names like this:

result=True
for dir in \
        "$PWD/dir1" \
        "$PWD/dir2" \
        "$PWD/dir3" 
do
    if ! [ -d "$dir" ]; then
        result=False
        break
    fi
done
for dir in \
        "$PWD/dir4" \
        "$PWD/dir5" \
        "$PWD/dir6" 
do
    if [ -e "$dir" ]; then                      # Note: no “!”
        result=False
        break
    fi
done
echo "$result"

I used [ -e "$dir" ] to test whether "$dir" exists; i.e., if dir5 exists but is a file, the result is False.  If you want only to test whether the names in the second group are directories, use [ -d "$dir" ], like in the first loop.

Since we’re talking about checking for the existence of things in the current working directory, it’s probably not necessary to specify $PWD/ on the names; just do

for dir in \
        "dir1" \
        "dir2" \
        "dir3" 
do
      ︙