old mode 100644
new mode 100755
@@ -1,11 +1,25 @@
#!/bin/sh
# SPDX-License-Identifier: GPL-2.0+
-#
-# Extract any RCU CPU stall warnings present in specified file.
-# Filter out clocksource lines. Note that preceding-lines excludes the
-# initial line of the stall warning but trailing-lines includes it.
-#
-# Usage: extract-stall.sh dmesg-file [ preceding-lines [ trailing-lines ] ]
+
+usage() {
+ echo Extract any RCU CPU stall warnings present in specified file.
+ echo Filter out clocksource lines. Note that preceding-lines excludes the
+ echo initial line of the stall warning but trailing-lines includes it.
+ echo
+ echo Usage: $(basename $0) dmesg-file [ preceding-lines [ trailing-lines ] ]
+ echo
+ echo Error: $1
+}
+
+# Terminate the script, if the argument is missing
+
+if test -f "$1" && test -r "$1"
+then
+ :
+else
+ usage "Console log file \"$1\" missing or unreadable."
+ exit 1
+fi
echo $1
preceding_lines="${2-3}"