For Loop Question

msb65 · #1 (**permalink**) 08-26-2008

Hi, I am writing a bash shell script. I will have a section of code devoted to a for loop:

for FILE in *.hdf *.L2; do
echo hello world
done

The complication is that sometimes there will not be any files with a ".hdf" extension, or sometimes there won't be any with a ".L2" extension. Since there are files with other extensions I can't just say "for FILE in *; do". How can I make my script loop through a number of times equal to the amount of files ending in .hdf or .L2, but not care if sometimes either of those filetypes doesn't exist?

Mike

era · #2 (**permalink**) 08-26-2008

What you have should work, just add the nullglob option.

Code:

set -o nullglob

msb65 · #3 (**permalink**) 08-26-2008

Hi era,

Thanks for the reply. Where in the code is that option set, and when does it stop taking effect?

deaconf19 · #4 (**permalink**) 08-26-2008

place the set -o nullglob at the beginning of your code

Code:

 set -o nullglob

Code:

 for FILE in *.hdf *.L2; do

era · #5 (**permalink**) 08-27-2008

The option is in effect until you change it again or until the current shell exits. In a shell script, the "current shell" exits when the script ends.

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