bash - Read file and run command in zsh

Question

So I generally create job files with a list of commands in it. Then I execute it like so

cat jobFile | while read a; do $a; done

Which always works in bash. However, I've just started working in Mac which apparently uses zsh. And this command fails with "no such file" etc. I've tested the job file by running few lines from it manually, so it should be fine.

I've found questions on zsh read inbut they tend to be reading in from variables e.g. $a=('a' 'b' 'c') or echo $a

Thank you for your answers!

Answer 1

In bash, unquoted parameter expansions always undergo word-splitting, so if a="foo bar", then $a expands to two words, foo and bar. As a command, this means running the command foo with an argument bar.

In zsh, parameter expansions to not undergo word-splitting by default, which means the same expansion $a would produce a single word foo bar, treated as the name of the command to execute.

In either case, relying on parameter expansion to "parse" a shell command is fragile; in addition to word-splitting, the expansion is subject to pathname expansion (globbing), and you are limited to simple commands and their arguments. No pipes, lists (&&, ||), or redirections allowed, as everything will be treated as the command name and a sequence of arguments.

What you want in both shells is to simply treat your job file as a shell script, which can be executed in the current shell using the . command:

. jobFile