Update to bash-4.1

3 files changed, 121 insertions, 1 deletions

diff --git a/examples/scripts/cat.sh b/examples/scripts/cat.sh
index 78106b2..3e65b3f 100644
--- a/examples/scripts/cat.sh
+++ b/examples/scripts/cat.sh
@@ -1,7 +1,7 @@
 shcat()
 {
 	while read -r ; do
-		echo "$REPLY"
+		printf "%s\n" "$REPLY"
 	done
 }
 
diff --git a/examples/scripts/timeout2 b/examples/scripts/timeout2
new file mode 100755
index 0000000..2c6fb77
--- /dev/null
+++ b/examples/scripts/timeout2
@@ -0,0 +1,29 @@
+#!/bin/sh
+
+# Author: P@draigBrady.com
+# V1.0  : Nov  3 2006
+#
+#  Execute a command with a timeout.
+#  If the timeout occurs the exit status is 128
+#
+#  Note there is an asynchronous equivalent of this
+#  script packaged with bash (under /usr/share/doc/ in my distro),
+#  which I only noticed after writing this.
+
+if [ "$#" -lt "2" ]; then
+    echo "Usage:   `basename $0` timeout_in_seconds command" >&2
+    echo "Example: `basename $0` 2 sleep 3 || echo timeout" >&2
+    exit 1
+fi
+
+cleanup()
+{
+    kill %1 2>/dev/null             #kill sleep $timeout if running
+    kill %2 2>/dev/null && exit 128 #kill monitored job if running
+}
+
+set -m               #enable job control
+trap "cleanup" 17    #cleanup after timeout or command
+timeout=$1 && shift  #first param is timeout in seconds
+sleep $timeout&      #start the timeout
+"$@"                 #start the job
diff --git a/examples/scripts/timeout3 b/examples/scripts/timeout3
new file mode 100644
index 0000000..5c19d2e
--- /dev/null
+++ b/examples/scripts/timeout3
@@ -0,0 +1,91 @@
+#!/bin/bash
+#
+# The Bash shell script executes a command with a time-out.
+# Upon time-out expiration SIGTERM (15) is sent to the process. If the signal
+# is blocked, then the subsequent SIGKILL (9) terminates it.
+#
+# Based on the Bash documentation example.
+
+# Hello Chet,
+# please find attached a "little easier"  :-)  to comprehend
+# time-out example.  If you find it suitable, feel free to include
+# anywhere: the very same logic as in the original examples/scripts, a
+# little more transparent implementation to my taste.
+#
+# Dmitry V Golovashkin <Dmitry.Golovashkin@sas.com>
+
+scriptName="${0##*/}"
+
+declare -i DEFAULT_TIMEOUT=9
+declare -i DEFAULT_INTERVAL=1
+declare -i DEFAULT_DELAY=1
+
+# Timeout.
+declare -i timeout=DEFAULT_TIMEOUT
+# Interval between checks if the process is still alive.
+declare -i interval=DEFAULT_INTERVAL
+# Delay between posting the SIGTERM signal and destroying the process by SIGKILL.
+declare -i delay=DEFAULT_DELAY
+
+function printUsage() {
+    cat <<EOF
+
+Synopsis
+    $scriptName [-t timeout] [-i interval] [-d delay] command
+    Execute a command with a time-out.
+    Upon time-out expiration SIGTERM (15) is sent to the process. If SIGTERM
+    signal is blocked, then the subsequent SIGKILL (9) terminates it.
+
+    -t timeout
+        Number of seconds to wait for command completion.
+        Default value: $DEFAULT_TIMEOUT seconds.
+
+    -i interval
+        Interval between checks if the process is still alive.
+        Positive integer, default value: $DEFAULT_INTERVAL seconds.
+
+    -d delay
+        Delay between posting the SIGTERM signal and destroying the
+        process by SIGKILL. Default value: $DEFAULT_DELAY seconds.
+
+As of today, Bash does not support floating point arithmetic (sleep does),
+therefore all delay/time values must be integers.
+EOF
+}
+
+# Options.
+while getopts ":t:i:d:" option; do
+    case "$option" in
+        t) timeout=$OPTARG ;;
+        i) interval=$OPTARG ;;
+        d) delay=$OPTARG ;;
+        *) printUsage; exit 1 ;;
+    esac
+done
+shift $((OPTIND - 1))
+
+# $# should be at least 1 (the command to execute), however it may be strictly
+# greater than 1 if the command itself has options.
+if (($# == 0 || interval <= 0)); then
+    printUsage
+    exit 1
+fi
+
+# kill -0 pid   Exit code indicates if a signal may be sent to $pid process.
+(
+    ((t = timeout))
+
+    while ((t > 0)); do
+        sleep $interval
+        kill -0 $$ || exit 0
+        ((t -= interval))
+    done
+
+    # Be nice, post SIGTERM first.
+    # The 'exit 0' below will be executed if any preceeding command fails.
+    kill -s SIGTERM $$ && kill -0 $$ || exit 0
+    sleep $delay
+    kill -s SIGKILL $$
+) 2> /dev/null &
+
+exec "$@"