foreach is a simple bash script which reads a given file/stdin line by line and executes a specific command with the line as argument.

Yup I did! But I am too lazy to memorize its complex argument passing techniques. So I wrote my own script.

Here is a simple example.

$ cat links.txt
https://www.youtube.com/watch?v=el0-J3tJs5M
https://www.youtube.com/watch?v=CBsXggn_4qA
https://www.youtube.com/watch?v=ZoCyVrl94yE

Now you want to execute youtube-dl with each line as argument. xargs might help in this case.

$ cat links.txt | xargs -L1 youtube-dl
[youtube] el0-J3tJs5M: Downloading ...
[youtube] CBsXggn_4qA: Downloading ...
[youtube] ZoCyVrl94yE: Downloading ...

But wait! xargs? -L1? That's too much to remember. And what if I want to use the argument in the middle of some commands? Like the following?

$ cat bands.txt
coldplay
dream theater
iron maiden
metallica
pink floyd

$ cat bands.txt | somemagiccommand echo i love {} and {} rocks
i love coldplay and coldplay rocks
i love dream theater and dream theater rocks
i love iron maiden and iron maiden rocks
i love metallica and metallica rocks
i love pink floyd and pink floyd rocks

foreach is that somemagiccommand. It replaces every {} in the command with the line from the file. You can use {} as many times as you want, wherever the position of the argument is.

$ cat distro.txt
kubuntu
debian
arch
freebsd
opensuse

$ foreach distro.txt echo {} is awesome # starts with {}
kubuntu is awesome
debian is awesome
arch is awesome
freebsd is awesome
opensuse is awesome

foreach can also be used without piping data into it. In such cases, the first argument will be taken as input filename. For example,

$ cat fruits.txt
apple
banana
cherry

$ foreach fruits.txt echo i love {} # ends with {}
i love apple
i love banana
i love cherry

You can skip {} if it is the only argument of the command you want to run. For example,

$ cat links.txt
https://www.youtube.com/watch?v=el0-J3tJs5M
https://www.youtube.com/watch?v=CBsXggn_4qA
https://www.youtube.com/watch?v=ZoCyVrl94yE

$ foreach links.txt youtube-dl # {} is not used here
[youtube] el0-J3tJs5M: Downloading ...
[youtube] CBsXggn_4qA: Downloading ...
[youtube] ZoCyVrl94yE: Downloading ...

This script relies on [ ! -t 0 ] to detect piped input, which may not work correctly in zsh or other non-bash, non-interactive terminals. In such environments, prefer the piped form (cat file.txt | foreach cmd) over the file-argument form (foreach file.txt cmd).

Download foreach and put it anywhere in your PATH. Or do the following.

sudo wget -O /usr/local/bin/foreach https://raw.githubusercontent.com/mdminhazulhaque/foreach/master/foreach
sudo chmod +x /usr/local/bin/foreach

• 2026-03-27 Fixed quoting, pipe detection, and sed injection issues
• 2017-05-05 Fixed an issue where last line was not being read

Open issues if you find any. You are also welcome to submit patches.