How to quote a string containing dollar sign $ and single quote '?

Question

My directory's name contains a $ and ', for example

:~$ export DIR=\$my\'dir
:~$ sh -c "ls $DIR"

How can I run above command without $my being expanded? I know the single quote doesn't work since the $DIR contains one.

Actually, the question came from using find command as follows:

:~$ find ./\$my\'dir -type d -exec sh -c 'ls "{}"' \;

It says ./\'dir: No such file or directory, if I remove the double quotes then it says unexpected EOF while looking for matching '.

Answer 1

Wow, some complex solutions here! I think all you need to do is this though:

find ./\$my\'dir -type d -exec sh -c 'ls "$1"' sh {} \;

Instead of putting the arguments into the sh command string, just use them as arguments to sh. Note the second sh is the value of $0, everything after that is a positional argument.

As for your full problem of finding directories not containing pdfs, you are usually always better off using find for this kind of thing rather than ls. This should be close to what you are looking for:

find . -type d \
  -exec sh -c '[ "$(find "$1" -maxdepth 1 -type f -iname "*.pdf")" = "" ]' sh {} \; \
  -print

Answer 2

Ok... here is a convoluted way to do it. It'll fail if the filenames contain new line characters.

  find . -type d -print0                          \ # get the directory list,
                                                  \ # separated by nulls
| xargs -0 ls -1 -d -Q --quoting-style=shell      \ # pick it with xargs, and use
                                                  \ # ls to apply shell quotes to each
                                                  \ # entry
| xargs -d '\n' -I '{}'                           \
        sh -c "ls {} | grep -qi \.pdf$ || echo {}"  # pick each quoted entry
                                                    # with xargs again
                                                    # (using -d, so it keeps the quotes)
                                                    # and insert it in the string

This relies on ls -Q --quoting-style=shell quoting with single quotes... otherwise, use single quotes on the argument to sh -c.

Ugh.

Answer 3

What you want is not easily possible because it is not possible to quote arbitrary strings from "outside" only (i.e. by enclosing in "" or ''). This could be done by quoting each character with \ but I don't see how that shall be done with simultaneously calling the shell.

This is possible:

echo "$DIR" | sed -e 's/./\\&/g' -e 's/^.*$/echo &/' | bash -s

But that cannot be put in an -exec statement. And the echo cannot be called from a shell because that shell would run into the quoting problem with the argument. You can make the find output the shell input:

find ./\$my\'dir -type d -print0  | xargs -0 -n 1 ls

But: You could write the string to a file and have the shell read it from there:

find ./\$my\'dir -maxdepth 0 -type d -fprint tmpfile -exec bash -c 'cat tmpfile' \;

Sorry, no, not even that works: find opens the file, does the -exec action and afterwards writes to the file... So... this works but is kind of crazy, of course:

find ./\$my\'dir -maxdepth 0 -type d -fprint tmpfile -exec bash -c '(sleep 1; cat tmpfile)&' \;

Answer 4

I'm not sure I understand your problem:

$ mkdir \$my\'dir
$ touch \$my\'dir/foo
$ ls $DIR
foo

As for finding subdirectories that don't include PDF files, just run this:

find . -type d -print0 | while IFS= read -r -d '' dir; do 
    [ $(find "$dir" -iname "*.pdf"  | wc -l) -gt 0 ] || echo $dir; 
done