From 64e9cac53b640e77c0ccfe71dd16174296c5985e Mon Sep 17 00:00:00 2001
From: James Pannacciulli <jpnc@jpnc.info>
Date: Sat, 11 Apr 2015 09:14:20 -0400
Subject: clean up option / variable names; add usage info

---
 pars.sh | 65 ++++++++++++++++++++++++++++++++++++++++++++++++++---------------
 1 file changed, 50 insertions(+), 15 deletions(-)

(limited to 'pars.sh')

diff --git a/pars.sh b/pars.sh
index f6741b7..5839690 100644
--- a/pars.sh
+++ b/pars.sh
@@ -1,52 +1,63 @@
 #!/bin/bash
 
 parssh () {
+    (( $# )) || {
+        _parssh_usage
+        return $?
+    }
     local origopts=$-
     set -m
+    local _parssh_prepend_host=true
     while [[ "$1" == -* ]]; do
         case ${1#-} in
             [0-9]*)
                 [[ "${1#-}" != *[^0-9]* ]] && {
-                    local parssh_concurrency=${1#-}
+                    local _parssh_concurrency=${1#-}
                 }
             ;;
-            fo|fouter)
+            s|-servers)
                 [[ -r "$2" ]] || {
                     echo "'$2': invalid file name or permissions issue"
                     return 99
                 }
-                local parssh_fouter="$2"
+                local _parssh_servers="$2"
                 shift
             ;;
-            fi|finner)
+            r|-rinput)
                 [[ -r "$2" ]] || {
                     echo "'$2': invalid file name or permissions issue"
                     return 98
                 }
-                local parssh_finner="$2"
+                local _parssh_rinput="$2"
                 shift
             ;;
-            p|prepend_host)
-                local parssh_prepend_host=true
+            b|-bare)
+                unset _parssh_prepend_host
+            ;;
+            h|-help)
+                _parssh_usage
+                return $?
             ;;
         esac
         shift
     done
 
-    [[ -z "$parssh_fouter" ]] && {
+    [[ -z "$_parssh_servers" ]] && {
         exec 9<&0
     } || {
-        exec 9<"$parssh_fouter"
+        exec 9<"$_parssh_servers"
     }
 
     while read host; do
-        while (( $(jobs -pr | wc -l) >= ${parssh_concurrency:-4} )); do
+        while (( $(jobs -pr | wc -l) >= ${_parssh_concurrency:-4} )); do
             sleep 1
         done
-        if [[ -z "$parssh_finner" ]]; then
-            ssh -no StrictHostKeyChecking=no $host "$@" | host_prepend &
+        if [[ -z "$_parssh_rinput" ]]; then
+            ssh -no StrictHostKeyChecking=no $host "$@" |\
+                _parssh_host_prepend &
         else
-            ssh -To StrictHostKeyChecking=no $host "$@" < "$parssh_finner" | host_prepend &
+            ssh -To StrictHostKeyChecking=no $host "$@" < "$_parssh_rinput" |\
+                _parssh_host_prepend &
         fi
     done <&9
     wait
@@ -54,7 +65,31 @@ parssh () {
     [[ "${origopts//[^m]/}" == "m" ]] || set +m
 }
 
-host_prepend ()
+_parssh_host_prepend ()
     while read -r; do
-        printf "${parssh_prepend_host+$host: }%s\n" "$REPLY"
+        printf "${_parssh_prepend_host+$host: }%s\n" "$REPLY"
     done
+
+_parssh_usage () {
+    printf '  %s\n'\
+        "SYNOPSIS"\
+        "parssh [-NUM] [-r|--rinput FILE] [-s|--servers FILE] [-b|--bare] [COMMANDS] [< SERVERS]"\
+        ""\
+        "DESCRIPTION"\
+        "  -NUM  (default: 4)"\
+        "     Number of concurrent ssh connections to maintain.  E.g. '-40'."\
+        "  -r FILE, --rinput FILE  (default: unset/inactive)"\
+        "     File to send as STDIN redirection on remote servers."\
+        "     (Can be used as replacement for or in conjunction with COMMANDS)."\
+        "  -s FILE, --servers FILE  (default: unset/inactive)"\
+        "     File to use as list of servers to run COMMANDS on."\
+        "     (Cannot be used in conjunction with a server list on STDIN)."\
+        "  -b, --bare  (default: unset/inactive)"\
+        "     Disable prepending of hostname to each output line returned by COMMANDS on SERVERS."\
+        "  COMMANDS"\
+        "     The list of commands to be executed remotely by SSH on each SERVER."\
+        "  < SERVERS"\
+        "     Unless '-s' flag is used, STDIN will be used as list of remote servers."\
+        "     (Deliniated by whitespace)."
+    return 1
+}
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