Execute on the basename of a find command

basenamecommand linefind

Suppose I have a directory structure as follows

test
test/a
test/b

Now I want to execute a command, such that in the . folder I can execute a command on the basename of the files a and b.

So basically, I want something like this, which I naively tried

find test -type f -exec touch `basename {}` \;

Only, this does not result in empty files a and b in the parent directory. Suppose that my touch command can only take a single argument.

This will result in a directory structure like this

a
b
test
test/a
test/b

I know how to do this in a bash script, but I am interested in single command solution.

Best Answer

Try the execdir option for find: it executes the command you specify in the directory of the file, using only its basename as the argument

From what I gather, you want to create "a" and "b" in the "main" directory. We can do that by combining $PWD and the -execdir option. Have a look at the solution below. (The && find … ls parts are for output only, so you can see the effects. You'll want to use the command before the &&.)

First, I set up the testing environment:

-----[ 15:40:17 ] (!6293) [ :-) ] janmoesen@mail ~/stack 
$ mkdir test && touch test/{a,b} && find . -exec ls -dalF {} +
drwxr-xr-x 3 janmoesen janmoesen 4096 2012-05-31 15:40 ./
drwxr-xr-x 2 janmoesen janmoesen 4096 2012-05-31 15:40 ./test/
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/a
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/b

This is what happens when you use a simple -exec — the original files are touched:

-----[ 15:40:30 ] (!6294) [ :-) ] janmoesen@mail ~/stack 
$ find test -type f -exec touch {} \; && find . -exec ls -dalF {} +
drwxr-xr-x 3 janmoesen janmoesen 4096 2012-05-31 15:40 ./
drwxr-xr-x 2 janmoesen janmoesen 4096 2012-05-31 15:40 ./test/
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/a
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/b

However, if we combine $PWD with the argument placeholder {} and use -execdir, we achieve what (I think) you want:

-----[ 15:40:57 ] (!6295) [ :-) ] janmoesen@mail ~/stack 
$ find test -type f -execdir touch "$PWD/{}" \; && find . -exec ls -dalF {} +
drwxr-xr-x 3 janmoesen janmoesen 4096 2012-05-31 15:41 ./
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:41 ./a
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:41 ./b
drwxr-xr-x 2 janmoesen janmoesen 4096 2012-05-31 15:40 ./test/
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/a
-rw-r--r-- 1 janmoesen janmoesen    0 2012-05-31 15:40 ./test/b

With `zsh`:

dirs=(*(/))
mkdir -- $^dirs/doc
touch -- $^dirs/doc/doc1.txt

(/) is a globbing qualifier, / means to select only directories.

$^array (reminiscent of rc's ^ operator) is to turn on a brace-like type of expansion on the array, so $^array/doc is like {elt1,elt2,elt3}/doc (where elt1, elt2, elt3 are the elements of the array).

One could also do:

mkdir -- *(/e:REPLY+=/doc:)
touch -- */doc(/e:REPLY+=/doc1.txt:)

Where e is another globbing qualifier that executes some given code on the file to select.

With `rc`/`es`/`akanga`:

dirs = */
mkdir -- $dirs^doc
touch -- $dirs^doc/doc1.txt

That's using the ^ operator which is like an enhanced concatenation operator.

rc doesn't support globbing qualifiers (which is a zsh-only feature). */ expands to all the directories and symlinks to directories, with / appended.

With `tcsh`:

set dirs = */
mkdir -- $dirs:gs:/:/doc::q
touch -- $dirs:gs:/:/doc/doc1.txt::q

The :x are history modifiers that can also be applied to variable expansions. :gs is for global substitute. :q quotes the words to avoid problems with some characters.

With `zsh` or `bash`:

dirs=(*/)
mkdir -- "${dirs[@]/%/doc}"
touch -- "${dirs[@]/%/doc/doc1.txt}"

${var/pattern/replace} is the substitute operator in Korn-like shells. With ${array[@]/pattern/replace}, it's applied to each element of the array. % there means at the end.

Various considerations:

dirs=(*/) includes directories and symlinks to directories (and there's no way to exclude symlinks other than using [ -L "$file" ] in a loop), while dir=(*(/)) (zsh extension) only includes directories (dir=(*(-/)) to include symlinks to directories without adding the trailing slash).

They exclude hidden dirs. Each shell has specific option to include hidden files).

If the current directory is writable by others, you potentially have security problems. As one could create a symlink there to cause you to create dirs or files where you would not want to. Even with solutions that don't consider symlinks, there's still a race condition as one may be able to replace a directory with a symlink in between the dirs=(*/) and the mkdir....

Bash – Rename files based on their parent directory using find/xargs command

These examples work in any POSIX shell and require no external programs.

This stores the Part*.mp3 files at the same level as the Project directory:

(cd Project && for i in Part*/audio.mp3; do echo mv "$i" ../"${i%/*}".mp3; done)

This keeps the Part*.mp3 files in the Project directory:

for i in Project/Part*/audio.mp3; do echo mv "$i" ./"${i%/*}".mp3; done

These solutions use the shell's pattern matching parameter expansion to produce the new filename.

 ${parameter%word}     Remove Smallest Suffix Pattern.  The word is expanded
                       to produce a pattern.  The parameter expansion then
                       results in parameter, with the smallest portion of
                       the suffix matched by the pattern deleted.

Best Answer

Related Solutions

Bash – How to Make Many Subdirectories at Once

With zsh:

With rc/es/akanga:

With tcsh:

With zsh or bash: