bash script read all the files in directory

Question

How do I loop through a directory? I know there is for f in /var/files;do echo $f;done; The problem with that is it will spit out all the files inside the directory all at once. I want to go one by one and be able to do something with the $f variable. I think the while loop would be best suited for that but I cannot figure out how to actually write the while loop.

Any help would be appreciated.

Answer 1

A simple loop should be working:

for file in /var/*
do
    #whatever you need with "$file"
done

See bash filename expansion

Answer 2

To write it with a while loop you can do:

ls -f /var | while read -r file; do cmd $file; done

The primary disadvantage of this is that cmd is run in a subshell, which causes some difficulty if you are trying to set variables. The main advantages are that the shell does not need to load all of the filenames into memory, and there is no globbing. When you have a lot of files in the directory, those advantages are important (that's why I use -f on ls; in a large directory ls itself can take several tens of seconds to run and -f speeds that up appreciably. In such cases 'for file in /var/*' will likely fail with a glob error.)

Answer 3

You can go without the loop:

find /path/to/dir -type f -exec /your/first/command \{\} \; -exec /your/second/command \{\} \; 

HTH