Bash scripting, loop through files in folder fails

Question

I'm looping through certain files (all files starting with MOVIE) in a folder with this bash script code:

for i in MY-FOLDER/MOVIE*
do

which works fine when there are files in the folder. But when there aren't any, it somehow goes on with one file which it thinks is named MY-FOLDER/MOVIE*.

How can I avoid it to enter the things after

do

if there aren't any files in the folder?

score 14 · Answer 1 · answered Sep 19 '11 at 21:36

14

With the nullglob option.

$ shopt -s nullglob
$ for i in zzz* ; do echo "$i" ; done
$

answered Sep 19 '11 at 21:36

Ignacio Vazquez-Abrams

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your code works for me even without the `nullglob` option, what am I doing wrong? – Dennis Golomazov Jun 06 '13 at 06:42
1

@DenisGolomazov: You have files that match. Try using a glob that matches no files. – Ignacio Vazquez-Abrams Jun 06 '13 at 12:50

Adam Liss · Accepted Answer · 2019-10-19T15:01:23.720

12

for i in $(find MY-FOLDER/MOVIE -type f); do
  echo $i
done

The find utility is one of the Swiss Army knives of linux. It starts at the directory you give it and finds all files in all subdirectories, according to the options you give it.

-type f will find only regular files (not directories).

As I wrote it, the command will find files in subdirectories as well; you can prevent that by adding -maxdepth 1

Edit, 8 years later (thanks for the comment, @tadman!)

You can avoid the loop altogether with

find . -type f -exec echo "{}" \;

This tells find to echo the name of each file by substituting its name for {}. The escaped semicolon is necessary to terminate the command that's passed to -exec.

edited Oct 19 '19 at 15:01

answered Sep 19 '11 at 21:38

Adam Liss

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1

find is swiss army knife, true. but used it such a way with for loop is prone to fail upon files with spaces. – bash-o-logist Sep 20 '11 at 05:08
1

Additionally, this will split on the `echo $i` since you left I unquoted. See [this](http://stackoverflow.com/a/7039579/3076724) for examples of better syntax. – Reinstate Monica Please Apr 17 '14 at 15:26
This won't work if your filenames have spaces in them. – tadman Oct 17 '19 at 00:03

score 3 · Answer 3 · answered Sep 20 '11 at 23:35

3

for file in MY-FOLDER/MOVIE*
do
  # Skip if not a file
  test -f "$file" || continue
  # Now you know it's a file.
  ...
done

answered Sep 20 '11 at 23:35

Idelic

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Bash scripting, loop through files in folder fails

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