Bash - 检查我是否对任何目录路径的父级有写权限

Question

In my bash script I have to create bunch of directories (NOT files) - /opt/some/path1/ and /opt/some/path2/ and so on.

Please note: In my case, /opt/some/ , the parent already exists, guaranteed. No validation required here.

How can I check if have write permissions to parent for my every mkdir /opt/some/path1/ and mkdir /opt/some/path2/ ...?

I learned that we can use -w for files so I tried this:

if [ -w /opt/some/path1/ ]; then echo "You have directory creation permissions"; else echo "You are having a rough day.!"; fi

Which "obviously fails" miserably because the directory I am going to create (the path), does not exist yet.

Is there a way we can use something similar to -w for files for directories? Or what I am missing here?

Answer 1

$ mkdir d1
$ [[ -w d1 ]] && echo Y
Y
$ mkdir d1/d11
$ chmod a-w d1
$ [[ ! -w d1 ]] && echo N
N
$ mkdir d1/d12
mkdir: d1/d12: Permission denied

you can check on a dir, which after all is a file

Answer 2

If I understand the question correctly, you want to check whether you have write access to the directory you want to create a subdirectory of, ie before creating /opt/some/path1/ you'd check write access to /opt/some/ . You can do that by using the dirname command to get the parent directory's path, then using the -w test on that . Note that mkdir still might fail for reasons other than permissions on the parent directory, so you still need to check it for errors. Something like this:

dirToCreate=/opt/some/path1/
if [ ! -w "$(dirname "$dirToCreate")" ]; then
    echo "Insufficient permissions to create $dirToCreate" >&2
else
    mkdir "$dirToCreate" || {
        echo "Error creating $dirToCreate (due to something other than permissions)" >&2
    }
fi