Cfrgtkky

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.

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.

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 &&

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 "$@".

Why not just:

if [ -d "dir1" -a -d "dir2" -a -d "dir3" ]; then

    echo True

else

    echo False

fi

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