Rename command not found when running a script

I'm trying to to execute a script, which uses the command rename.

When I execute it, I get a message rename: command not found. Any ideas?

if [[ -z '$3' ]]; then shopt -s dotglob rename "$EXPRESSION" ./*
else rename "$EXPRESSION" "$3"
fi

2 Answers

I just had to install the rename package.

sudo apt install rename

My Ubuntu has a man page for rename(1) on fresh install, but running rename gives a CNF error.

The man page style suggests that the command belongs to GNU Core Utilities, but confusingly it actually is rename.ul (Ubuntu Bionic / Disco / Eoan + Debian Buster). This command corresponds to the mysterious rename(1) page.

If you install rename package, the new man page is rename(1p). It's a Perl script, not coreutils.