From d7225edc3e72598742f7c6e9e661bec797ad33d8 Mon Sep 17 00:00:00 2001
From: James Pannacciulli <jpnc@jpnc.info>
Date: Sun, 12 Apr 2015 21:24:47 -0700
Subject: Add internal support for redirecting or copying stdout/err to files

---
 pars.sh | 70 +++++++++++++++++++++++++++++++++++++++++++++++++++++++----------
 1 file changed, 60 insertions(+), 10 deletions(-)

diff --git a/pars.sh b/pars.sh
index 5839690..93b8ca6 100644
--- a/pars.sh
+++ b/pars.sh
@@ -5,9 +5,14 @@ parssh () {
         _parssh_usage
         return $?
     }
-    local origopts=$-
+
+    local _parssh_origopts=$-
     set -m
+
+    local _parssh_outfun=_parssh_out
     local _parssh_prepend_host=true
+    local _parssh_ssh=_parssh_ssh
+
     while [[ "$1" == -* ]]; do
         case ${1#-} in
             [0-9]*)
@@ -29,11 +34,30 @@ parssh () {
                     return 98
                 }
                 local _parssh_rinput="$2"
+                local _parssh_ssh=_parssh_ssh_rinput
                 shift
             ;;
             b|-bare)
                 unset _parssh_prepend_host
             ;;
+            o|-out)
+                touch "${2}.{out,err}" || {
+                    echo "'${2}.{out,err}': unable to write / modify file"
+                    return 97
+                }
+                local _parssh_outprefix="$2"
+                local _parssh_outfun=_parssh_out_redirect
+                shift
+            ;;
+            t|-tee)
+                touch "${2}.{out,err}" || {
+                    echo "'${2}.{out,err}': unable to write / modify file"
+                    return 96
+                }
+                local _parssh_outprefix="$2"
+                local _parssh_outfun=_parssh_out_copy
+                shift
+            ;;
             h|-help)
                 _parssh_usage
                 return $?
@@ -52,17 +76,23 @@ parssh () {
         while (( $(jobs -pr | wc -l) >= ${_parssh_concurrency:-4} )); do
             sleep 1
         done
-        if [[ -z "$_parssh_rinput" ]]; then
-            ssh -no StrictHostKeyChecking=no $host "$@" |\
-                _parssh_host_prepend &
-        else
-            ssh -To StrictHostKeyChecking=no $host "$@" < "$_parssh_rinput" |\
-                _parssh_host_prepend &
-        fi
-    done <&9
+        $_parssh_ssh "$@" 2> >(_parssh_host_prepend >&2) |\
+            _parssh_host_prepend &
+    done <&9 2> >($_parssh_outfun err >&2) |\
+        $_parssh_outfun out
+
     wait
+
     exec 9>&-
-    [[ "${origopts//[^m]/}" == "m" ]] || set +m
+    [[ "${_parssh_origopts//[^m]/}" == "m" ]] || set +m
+}
+
+_parssh_ssh () {
+    ssh -no StrictHostKeyChecking=no $host "$@"
+}
+
+_parssh_ssh_rinput () {
+    ssh -To StrictHostKeyChecking=no $host "$@" < "$_parssh_rinput"
 }
 
 _parssh_host_prepend ()
@@ -70,8 +100,24 @@ _parssh_host_prepend ()
         printf "${_parssh_prepend_host+$host: }%s\n" "$REPLY"
     done
 
+_parssh_out () {
+    cat -
+}
+
+_parssh_out_redirect () {
+    local _parssh_out_stream="$1"
+    cat - > "${_parssh_outprefix}.${_parssh_out_stream}"
+}
+
+_parssh_out_copy () {
+    local _parssh_out_stream="$1"
+    tee "${_parssh_outprefix}.${_parssh_out_stream}"
+}
+
 _parssh_usage () {
     printf '  %s\n'\
+        "parssh: Parallel SSH orchestration in a Bash session."\
+        ""\
         "SYNOPSIS"\
         "parssh [-NUM] [-r|--rinput FILE] [-s|--servers FILE] [-b|--bare] [COMMANDS] [< SERVERS]"\
         ""\
@@ -86,6 +132,10 @@ _parssh_usage () {
         "     (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."\
+        "  -o PREFIX, --out PREFIX  (default: unset/inactive)"\
+        "     Redirect STDOUT / STDERR to PREFIX.out / PREFIX.err, respectively."\
+        "  -t PREFIX, --tee PREFIX  (default: unset/inactive)"\
+        "     Copy STDOUT / STDERR to PREFIX.out / PREFIX.err, respectively."\
         "  COMMANDS"\
         "     The list of commands to be executed remotely by SSH on each SERVER."\
         "  < SERVERS"\
-- 
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