Question

In a shell script (in .zshrc) I am trying to execute a command that is stored as a string in another variable. Various sources on the web say this is possible, but I’m not getting the behavior i expect. Maybe it’s the ~ at the beginning of the command, or maybe it’s the use of sudo, I’m not sure. Any ideas? Thanks

function update_install()
{
    # builds up a command as a string...
    local install_cmd="$(make_install_command $@)"
    # At this point the command as a string looks like: "sudo ~some_server/bin/do_install arg1 arg2"
    print "----------------------------------------------------------------------------"
    print "Will update install"
    print "With command: ${install_cmd}"
    print "----------------------------------------------------------------------------"
    echo "trying backticks"
    `${install_cmd}`
    echo "Trying \$()"
    $(${install_cmd})
    echo "Trying \$="
    $=install_cmd
}

Output:

Will update install
With command: sudo ~some_server/bin/do_install arg1 arg2

trying backticks
update_install:9: no such file or directory: sudo ~some_server/bin/do_install arg1 arg2
Trying $()
update_install:11: no such file or directory: sudo ~some_server/bin/do_install arg1 arg2
Trying $=
sudo ~some_server/bin/do_install arg1 arg2: command not found

Answer 1

Use eval:

eval ${install_cmd}