Add command to list commands with prefix

libexec/lasher-_commands

@@ -0,0 +1,32 @@
+#!/usr/bin/env bash
+#
+# Summary: List all available commands with a prefix
+# Usage: lasher _commands <prefix>
+#
+# Looks for executable files prefixed with prefix- and
+# displays each suffix as an available command.
+#
+# This is supposed to be used from other scripts.
+
+set -e
+
+if [ "$#" -ne 1 ]; then
+  lasher-help _commands
+  exit 1
+fi
+
+prefix="$1"
+
+IFS=: paths=($PATH)
+
+shopt -s nullglob
+
+{ for path in "${paths[@]}"; do
+    for command in "${path}/$prefix-"*; do
+      command="${command##*$prefix-}"
+      if [[ ! "$command" == _* ]]; then
+        echo ${command}
+      fi
+    done
+  done
+} | sort | uniq

tests/lasher-_commands.bats

@@ -0,0 +1,22 @@
+#!/usr/bin/env bats
+
+load test_helper
+
+@test "without arguments prints usage" {
+  run lasher-_commands
+  assert_failure
+  assert_line "Usage: lasher _commands <prefix>"
+}
+
+@test "lists commands" {
+  run lasher-_commands lasher
+  assert_success
+  assert_line help
+  assert_line new-command
+}
+
+@test "does not list hidden commands" {
+  run lasher-_commands lasher
+  assert_success
+  refute_line _commands
+}