unitproc/bktemp-appendArgTar

   1 #!/bin/bash
   2
   3 # Desc: Template function to write data supplied as argument
   4
   5 yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
   6 die() { yell "$*"; exit 111; }
   7 try() { "$@" || die "cannot $*"; }
   8 appendArgTar(){
   9     # Desc: Writes first argument to temporary file with arguments as options, then appends file to tar
  10     # Usage: appendArgTar "$(echo "Data to be written.")" [name of file to be inserted] [tar path] [temp dir] ([cmd1] [cmd2] [cmd3] [cmd4]...)
  11     # Version: 1.0.6
  12     # Input: arg1: data to be written
  13     #        arg2: file name of file to be inserted into tar
  14     #        arg3: tar archive path (must exist first)
  15     #        arg4: temporary working dir
  16     #        arg5+: command strings (ex: "gpsbabel -i nmea -f - -o kml -F - ")
  17     # Output: file written to disk
  18     # Example: decrypt multiple large files in parallel
  19     #          appendArgTar "$(cat /tmp/largefile1.gpg)" "largefile1" $HOME/archive.tar /tmp "gpg --decrypt" &
  20     #          appendArgTar "$(cat /tmp/largefile2.gpg)" "largefile2" $HOME/archive.tar /tmp "gpg --decrypt" &
  21     #          appendArgTar "$(cat /tmp/largefile3.gpg)" "largefile3" $HOME/archive.tar /tmp "gpg --decrypt" &
  22     # Depends: bash 5, tar 1, yell()
  23     # Ref/Attrib: Using 'eval' to construct command strings https://askubuntu.com/a/476533
  24
  25     local fn fileName tarPath tmpDir cmd0 cmd1 cmd2 cmd3 cmd4
  26
  27     # Save function name
  28     fn="${FUNCNAME[0]}";
  29     #yell "DEBUG:STATUS:$fn:Finished appendArgTar()."
  30
  31     # Set file name
  32     if ! [ -z "$2" ]; then fileName="$2"; else yell "ERROR:$fn:Not enough arguments."; exit 1; fi
  33
  34     # Check tar path is a file
  35     if [ -f "$3" ]; then tarPath="$3"; else yell "ERROR:$fn:Tar archive arg not a file."; exit 1; fi
  36
  37     # Check temp dir arg
  38     if ! [ -z "$4" ]; then tmpDir="$4"; else yell "ERROR:$fn:No temporary working dir set."; exit 1; fi
  39
  40     # Set command strings
  41     if ! [ -z "$5" ]; then cmd1="$5"; else cmd1="cat "; fi # command string 1
  42     if ! [ -z "$6" ]; then cmd2="$6"; else cmd2="cat "; fi # command string 2
  43     if ! [ -z "$7" ]; then cmd3="$7"; else cmd3="cat "; fi # command string 3
  44     if ! [ -z "$8" ]; then cmd4="$8"; else cmd4="cat "; fi # command string 4
  45
  46     # Input command
  47     cmd0="echo \"\$1\""
  48
  49     # # Debug
  50     # yell "DEBUG:STATUS:$fn:cmd0:$cmd0"
  51     # yell "DEBUG:STATUS:$fn:cmd1:$cmd1"
  52     # yell "DEBUG:STATUS:$fn:cmd2:$cmd2"
  53     # yell "DEBUG:STATUS:$fn:cmd3:$cmd3"
  54     # yell "DEBUG:STATUS:$fn:cmd4:$cmd4"
  55     # yell "DEBUG:STATUS:$fn:fileName:$fileName"
  56     # yell "DEBUG:STATUS:$fn:tarPath:$tarPath"
  57     # yell "DEBUG:STATUS:$fn:tmpDir:$tmpDir"
  58
  59     # Write to temporary working dir
  60     eval "$cmd0 | $cmd1 | $cmd2 | $cmd3 | $cmd4" > "$tmpDir"/"$fileName";
  61
  62     # Append to tar
  63     try tar --append --directory="$tmpDir" --file="$tarPath" "$fileName";
  64     #yell "DEBUG:STATUS:$fn:Finished appendArgTar()."
  65 } # Append Bash var to file appended to Tar archive
  66
  67 #==BEGIN sample code==
  68 myTar="/tmp/$(date +%s).tar";
  69 myTmpDir="/dev/shm"
  70 try tar --create --file="$myTar" --files-from=/dev/null ;
  71 myVar="how are you doing?"
  72 appendArgTar "$myVar" "$(date +%s)..LOUD_insidetar" "$myTar" "$myTmpDir" "tee /tmp/$(date +%s)..outsidetar " "tr '[:lower:]' '[:upper:]'" && \
  73     echo "Created $myTar using $myTmpDir as temp working dir."
  74 #==END sample code==
  75
  76 # Author: Steven Baltakatei Sandoval
  77 # License: GPLv3+