unix/waiton.sh: Rewrite to support multiple processes

1 files changed, 97 insertions, 23 deletions

diff --git a/unix/waiton.sh b/unix/waiton.sh
index 988d3d3..0689106 100755
--- a/unix/waiton.sh
+++ b/unix/waiton.sh
@@ -1,29 +1,103 @@
 #!/bin/sh
 #
-# Wait for a UNIX process to finish
-# Jon Cairns
-# http://blog.joncairns.com/2013/03/wait-for-a-unix-process-to-finish/
-# 2013-03-20
+# Copyright (c) 2018-2019 Aaron LI <aly@aaronly.me>
+# MIT License
 #
+# Wait for process(s) to finish ...
+#
+# Credit: http://blog.joncairns.com/2013/03/wait-for-a-unix-process-to-finish/
+#
+
+me="${0##*/}"
+
+has_proc() {
+    ps -p $1 >/dev/null 2>&1
+}
+
+get_proc_cmd() {
+    if has_proc $1; then
+        ps -p $1 -o args=
+    else
+        echo "(not found)"
+        return 1
+    fi
+}
+
+usage() {
+    cat <<_EOF_
+
+Wait for process(s) to finish ...
+
+usage:
+    ${me} [-t interval] <pid1> [<pid2> ...]
+
+options:
+    -t : number of seconds between every check.
+         (default: 5)
+
+example:
+    ${me} 123 456 && command ...
 
-case "$1" in
-    -h|--help|"")
-        echo "usage: ${0##*/} <pid>" >&2
-        exit 1
+_EOF_
+    exit 1
+}
+
+
+interval=5
+while getopts :ht: opt; do
+    case ${opt} in
+    h)
+        usage
+        ;;
+    t)
+        interval="${OPTARG}"
+        ;;
+    \?)
+        echo "${me}: invalid option -${OPTARG}"
+        usage
+        ;;
+    :)
+        echo "${me}: option -${OPTARG} requires an argument"
+        usage
         ;;
-esac
-
-pid="$1"
-me="${0##*/} (pid=$$)"
-name=$(ps -p ${pid} -o args=)
-if [ $? -eq 0 ]; then
-    echo "${me}: waiting for process (pid=${pid}, ${name}) to finish ..."
-    while ps -p ${pid} >/dev/null 2>&1; do
-        echo -n .
-        sleep 3
+    esac
+done
+
+shift $((${OPTIND} - 1))
+[ $# -eq 0 ] && usage
+
+echo "${me}: waiting for following process(s) to finish ..."
+pids="$@"
+nwait=0
+for p in ${pids}; do
+    cmd=$(get_proc_cmd ${p})
+    ret=$?
+    echo "* [pid: ${p}] ${cmd}"
+    if [ ${ret} -eq 0 ]; then
+        nwait=$((${nwait} + 1))
+        eval _has_${p}=yes
+    fi
+done
+
+echo -n "${me}: "
+while [ ${nwait} -ne 0 ]; do
+    nwait=0
+    for p in ${pids}; do
+        key="_has_${p}"
+        eval last=\$${key}
+        if has_proc ${p}; then
+            nwait=$((${nwait} + 1))
+            eval ${key}=yes
+        elif [ -n "${last}" ]; then
+            echo
+            echo "${me}: pid=${p} exited."
+            echo -n "${me}: "
+            eval ${key}=
+        fi
     done
-    echo
-else
-    echo "${me}: failed to find process with PID ${pid}" >&2
-    exit 2
-fi
+    echo -n "${nwait}."
+    sleep ${interval}
+done
+
+echo "done"
+exit 0