I am looking for a complimentary function to pkgs.writeShellScript, which I should expect to be named pkgs.runShellScript, which takes a derivation suffix (or the name of the script), and the contents of the script. I would suppose you use it something like let script = name: pkgs.runShellScript…

so just use the multiline Nix syntax? ''. pkgs.runCommand "hello" { ECHO_VAR = "hello"; } '' echo $ECHO_VAR > $out ${lib.getExe pkgs.cowsay} "The value of ECHO_VAR is inside $out" '';