lib.sh: Don't require perl in installed(), instead use awk.

diff --git a/lib.sh b/lib.sh
index 1fa3c8fc0fedaea09f27b91769f1f93218a793fb..1862444f7f560fd9b6eb1922da19423b01459fc0 100644 (file)
--- a/lib.sh
+++ b/lib.sh
@@ -11,7 +11,11 @@ unset LS_COLORS
 # Check if the given program is installed. Returns 0 if it exists, 1
 # otherwise; so it can be used in if.
 installed() {
-    which $1 2>&1 | perl -e '$_ = <>; if (not m{^/}) { exit 1 }'
+    # Thanks to Rado in #awk on Freenode (2010-03-29 01:34) for the END tip to
+    # also work with empty stdin, and to prince_jammys in #awk on Freenode
+    # (2010-03-29 02:20) for a shorter syntax for "$0 !~".
+    which $1 2>&1 | awk '{ if (!/^\//) exit 1 }
+                         END { if (NR == 0) exit 1 }'
 }
 
 # Print the current OS. The following OS are supported at the moment: