|
Size: 2217
Comment: put bash solutions at top, removed bash-specific non-array solution (what's wrong with arrays?), removed ls -A solutions (if you want to not use a specific shell you may as well TRY to be portable)
|
Size: 2342
Comment: I forgot about dot files. The portable solution is now even uglier, and relies on .* expanding to exactly . .. in empty dirs... will it? Maybe add other solutions with warnings
|
| Deletions are marked like this. | Additions are marked like this. |
| Line 8: | Line 8: |
| In BASH, you can do this safely and easily with the nullglob option (which changes the behaviour of [:glob:globbing]), and arrays: | In BASH, you can do this safely and easily with the nullglob and dotglob options (which change the behaviour of [:glob:globbing]), and arrays: |
| Line 11: | Line 11: |
| shopt -s nullglob | shopt -s nullglob dotglob |
| Line 14: | Line 14: |
| shopt -u nullglob | shopt -u nullglob dotglob |
| Line 49: | Line 49: |
| if [ "`printf %s foo/*`" = 'foo/*' ] && [ ! -e 'foo/*' ] | cd foo if [ "`printf '%s %s %s' .* *`" = '. .. *' ] && [ ! -f '*' ] |
| Line 51: | Line 52: |
| echo "foo is empty" | echo "directory is empty" |
| Line 55: | Line 56: |
| Yes, it's ugly, but it should be more portable than anything depending on ls output. | Yes, it's extremely ugly, but it should be more portable than anything depending on ls output. Even ls -A solutions can break (HPUX for one, if you are root). |
How can I check whether a directory is empty or not? How do I check for any *.mpg files?
I just deleted three completely wrong answers from this question. Please, people, make sure that when you add to the FAQ, your answers
- answer the question that was asked, and
actually work
Thanks. -- GreyCat
In BASH, you can do this safely and easily with the nullglob and dotglob options (which change the behaviour of [:glob:globbing]), and arrays:
shopt -s nullglob dotglob
files=(*)
(( ${#files[*]} )) || echo directory is empty
shopt -u nullglob dotglobAs you can see we unset the nullglob after using it, to prevent it affecting other globs in the script in unexpected ways. nullglob also simplifies various other operations:
shopt -s nullglob
for i in *.zip; do
blah blah "$i" # No need to check $i is a file.
done
shopt -u nullglobWithout the nullglob, that would have to be:
for i in *.zip; do
[[ -f $i ]] || continue # If no .zip files, i becomes *.zip
blah blah "$i"
done(You may want to use the latter anyway, if there's a possibility that the glob may match directories in addition to files.)
In fact, you may wish to avoid the direct question altogether. Usually people want to know whether a directory is empty... because they want to do something involving the files therein, etc. Look to the larger question. For example, one of these [:UsingFind:find-based examples] may be an appropriate solution:
find "$somedir" -type f -exec echo Found unexpected file {} \;
find "$somedir" -maxdepth 0 -empty -exec echo {} is empty. \; # GNU/BSD
find "$somedir" -type d -empty -exec cp /my/configfile {} \; # GNU/BSDIf your script needs to run with various shell implementations, you can try using an external program like python, perl, or find as indicated above, or you can try something like:
cd foo
if [ "`printf '%s %s %s' .* *`" = '. .. *' ] && [ ! -f '*' ]
then
echo "directory is empty"
fiYes, it's extremely ugly, but it should be more portable than anything depending on ls output. Even ls -A solutions can break (HPUX for one, if you are root).