bash best practice : scripting actions to be done in all current subdirectories

billywayne · 07-29-2009, 06:31 PM

Hello!

I've been writing bash scripts which perform actions in all the subdirectories in a current directory.

I've implemented this by executing a for loop which recurses over every subdirectory. My question is, how exactly should I obtain the names of the current subdirecties?

What I've been doing is this ...

Code:

for SUBDIR in `ls -d /*` ; do
   cd $SUBDIR
   foo
   bar
done

But this sometimes works, sometimes doesn't and I'm sure this isn't best practice.

In the meantime, I've changed to using

Code:

for SUBDIR in `find . -maxdepth 1 -mindepth 1 -type d` ; do
    cd $SUBDIR
    foo
    bar
done

Actually, I simply created an alias for this particular find command:

Code:

alias subdirs='find . -maxdepth 1 -mindepth 1 -type d'

and then write the for loop with

Code:

for SUBDIR in `subdirs` ; do ...

But I want to know what is considered best practice for recursively entering subdirectories and executing commands from within them. Please keep in mind that I really do need to actually cd into each directory to perform the actions from within the subdirectory.

Any and all advice appreciated.

Thanks!

billywayne

neonsignal · 07-29-2009, 10:11 PM

I don't know about best practice, but would this way be helpful?

Code:

find * -maxdepth 0 -type d -exec bash -c "cd \"{}\"; foo; bar" \;

The disadvantage is that it invokes a new shell for each subdirectory. The advantage is that for very large directories it does not have to
generate the whole list before doing anything.

The reason for the quotes around the 'cd' parameter is that some directories may have spaces in the name.

I was hoping to do something similar with the '-execdir' action on the find, but couldn't work out a way to make it only happen once on each subdirectory.

billywayne · 07-31-2009, 09:04 PM

thanks for the reply. i received an email when you replied two days ago, but strangely whenever I clicked on the link to view the thread, your reply wasn't showing up, until just now. weird.

i hadn't considered incorporating the commands directory into the 'find' command. It seems 'find' is more flexible than i had imagined.

thanks again.

neonsignal · 07-31-2009, 09:18 PM

Quote:

strangely whenever I clicked on the link to view the thread, your reply wasn't showing up

Yes, I have the same issue - I find on LQ that I always get cached copies of pages I have looked at recently, and have to press F5 to refresh.

billywayne · 08-01-2009, 08:42 PM

Quote:

Originally Posted by neonsignal

Yes, I have the same issue - I find on LQ that I always get cached copies of pages I have looked at recently, and have to press F5 to refresh.

Thanks for the hint!