Cannot figure out how to fix shellcheck complaint that I should not use a glob as a command when starting one script from another

Question

Example script:

#!/bin/bash

printf '1\n1\n1\n1\n' | ./script2*.sh >/dev/null 2>/dev/null

Shellcheck returns the following:

In script1.sh line 3:
printf '1\n1\n1\n1\n' | ./script2*.sh >/dev/null 2>/dev/null
                        ^-- SC2211: This is a glob used as a command name. Was it supposed to be in ${..}, array, or is it missing quoting?

According to https://github.com/koalaman/shellcheck/wiki/SC2211, there should be no exceptions to this rule.

Specifically, it suggests "If you want to specify a command name via glob, e.g. to not hard code version in ./myprogram-*/foo, expand to array or parameters first to allow handling the cases of 0 or 2+ matches."

The reason I'm using the glob in the first place is that I append or change the date to any script that I have just created or changed. Interestingly enough, when I use "bash script2*.sh" instead of "./script2*.sh" the complaint goes away.

Have I fixed the problem or I am tricking shellcheck into ignoring a problem that should not be ignored? If I am using bad bash syntax, how might I execute another script that needs to be referenced to using a glob the proper way?

score 2 · Accepted Answer · answered Feb 27 '18 at 21:39

The problem with this is that ./script2*.sh may end up running

./script2-20171225.sh ./script2-20180226.sh ./script2-copy.sh

which is a strange and probably unintentional thing to do, especially if the script is confused by such arguments, or if you wanted your most up-to-date file to be used. Your "fix" has the same fundamental problem.

The suggestion you mention would take the form:

array=(./script2*.sh)
[ "${#array[@]}" -ne 1 ] && { echo "Multiple matches" >&2; exit 1; }
"${array[0]}"

and guard against this problem.

Since you appear to assume that you'll only ever have exactly one matching file to be invoked without parameters, you can turn this into a function:

runByGlob() {
  if (( $# != 1 ))
  then
    echo "Expected exactly 1 match but found $#: $*" >&2
    exit 1
  elif command -v "$1" > /dev/null 2>&1
  then
    "$1"
  else
    echo "Glob is not a valid command: $*" >&2
    exit 1
  fi
}

whatever | runByGlob ./script2*.sh

Now if you ever have zero or multiple matching files, it will abort with an error instead of potentially running the wrong file with strange arguments.

Cannot figure out how to fix shellcheck complaint that I should not use a glob as a command when starting one script from another

1 Answers1