detect if a command is available

diff --git a/bash/detect-if-installed.sh b/bash/detect-if-installed.sh
new file mode 100644 (file)
index 0000000..21f8ef3
--- /dev/null
+++ b/bash/detect-if-installed.sh
@@ -0,0 +1,17 @@
+#!/bin/bash
+
+# Simple example how to detect if a command is available
+# otherwise print message and exit
+
+# This program is free software: you can redistribute it and/or modify
+# it under the terms of the COMMON DEVELOPMENT AND DISTRIBUTION LICENSE
+#
+# You should have received a copy of the
+# COMMON DEVELOPMENT AND DISTRIBUTION LICENSE (CDDL) Version 1.0
+# along with this program.  If not, see http://www.sun.com/cddl/cddl.html
+
+# 2019 https://www.bananas-playground.net
+
+# In this example we need curl to be iinstalled.
+# If not print message and exit.
+command -v curl >/dev/null 2>&1 || { echo >&2 "I require curl (https://curl.haxx.se/) but it's not installed.  Aborting."; exit 1; }