Anchor(faq15)

How can I run a command on all files with the extension .gz?

Often a command already accepts several files as arguments, e.g. 

    zcat *.gz

(One some systems, you would use gzcat instead of zcat. If neither is available, or if you don't care to play guessing games, just use gzip -dc instead.) If an explicit loop is desired, or if your command does not accept multiple filename arguments in one invocation, the for loop can be used: 

    # Bourne
    for file in *.gz
    do
        echo "$file"
        # do something with "$file"
    done

To do it recursively, you should use a loop, plus the [:UsingFind:find] command: 

    # Bash
    while read file; do
        echo "$file"
        # do something with "$file"
    done < <(find . -name '*.gz' -print)

For more hints in this direction, see [:BashFAQ/020:FAQ #20]. To see why the find command comes after the loop instead of before it, see [:BashFAQ/024:FAQ #24].