From 1f2681284c87d5cde538a0eb18c49b0916b9743e Mon Sep 17 00:00:00 2001
From: Steven Baltakatei Sandoval <baltakatei@gmail.com>
Date: Wed, 1 Jul 2020 20:27:41 +0000
Subject: [PATCH] feat(bkgpslog):Append to preexisting tar if possible

---
 exec/bkgpslog | 15 +++++++++++++--
 1 file changed, 13 insertions(+), 2 deletions(-)

diff --git a/exec/bkgpslog b/exec/bkgpslog
index d0dde14..840a0c6 100755
--- a/exec/bkgpslog
+++ b/exec/bkgpslog
@@ -698,8 +698,19 @@ main() {
     PATHOUT_TAR="$DIR_OUT"/"$(dateShort)".."$SCRIPT_HOSTNAME""_location""$CMD_COMPRESS_SUFFIX""$CMD_ENCRYPT_SUFFIX".tar 
     ## Write bkgpslog version to DIR_TMP/VERSION
     echo "$0"" Version:""$SCRIPT_VERSION" >> "$DIR_TMP/VERSION" && vbm "DEBUG:VERSION created."
-    ## Create empty tar archive at PATHOUT_TAR
-    try tar --create --directory="$DIR_TMP" --file="$PATHOUT_TAR" --files-from=/dev/null && vbm "DEBUG:""$PATHOUT_TAR"" created."
+    ## Check if PATHOUT_TAR already exists.
+    if [[ -f "$PATHOUT_TAR" ]]; then
+	### Check if preexisting tar is appendable.
+	PATHOUT_APPENDTEST="$DIR_TMP"/"$(dateTimeShort)..append_test.txt"
+	echo "$(dateTimeShort)" >> "$PATHOUT_APPENDTEST"; && vbm "DEBUG:""$PATHOUT_APPENDTEST"" created."
+	if ! tar --append --directory="$DIR_TMP" --file="$PATHOUT_TAR" "$(basename "$PATHOUT_APPENDTEST")"; then
+	    ### If not appendable, label tar broken, move tar, proceed.
+	    mv "$PATHOUT_TAR" "${PATHOUT_TAR%.*}""-broken$(dateTimeShort)".tar
+	fi
+    else
+	### If (no preexisting|appendable) tar found, create empty tar archive at PATHOUT_TAR
+	try tar --create --directory="$DIR_TMP" --file="$PATHOUT_TAR" --files-from=/dev/null && vbm "DEBUG:""$PATHOUT_TAR"" created."
+    fi	
     ## Append VERSION file to PATHOUT_TAR
     try tar --append --directory="$DIR_TMP" --file="$PATHOUT_TAR" "VERSION" && vbm "DEBUG:VERSION added to $PATHOUT_TAR"
     
-- 
2.30.2