unitproc/bktemp-checkMakeTar

   1 #!/bin/bash
   2
   3 # Desc: Checks that a valid tar archive exists, creates one otherwise
   4
   5
   6 yell() { echo "$0: $*" >&2; }      #o Yell, Die, Try Three-Fingered Claw technique
   7 die() { yell "$*"; exit 111; }     #o Ref/Attrib: https://stackoverflow.com/a/25515370
   8 try() { "$@" || die "cannot $*"; } #o
   9
  10 #===BEGIN Declare local script functions===
  11 checkMakeTar() {
  12     # Desc: Checks that a valid tar archive exists, creates one otherwise
  13     # Usage: checkMakeTar [ path ]
  14     # Version: 1.0.0
  15     # Input: arg1: path of tar archive
  16     # Output: exit code 0 : tar readable
  17     #         exit code 1 : tar missing; created
  18     #         exit code 2 : tar not readable; moved; replaced
  19     # Depends: try, tar, date
  20     local PATH_TAR returnFlag0 returnFlag1 returnFlag2
  21     PATH_TAR="$1"
  22
  23     # Check if file is a valid tar archive
  24     if tar --list --file="$PATH_TAR" 1>/dev/null 2>&1; then
  25         ## T1: return success
  26         returnFlag0="tar valid";
  27     else
  28         ## F1: Check if file exists
  29         if [[ -f "$PATH_TAR" ]]; then
  30             ### T: Rename file
  31             try mv "$PATH_TAR" "$PATH_TAR""--broken--""$(date +%Y%m%dT%H%M%S)" && \
  32                 returnFlag1="tar moved";
  33         else
  34             ### F: -
  35             :
  36         fi
  37         ## F2: Create tar archive, return 0
  38         try tar --create --file="$PATH_TAR" --files-from=/dev/null && \
  39             returnFlag2="tar created";
  40     fi
  41
  42     # Determine function return code
  43     if [[ "$returnFlag0" = "tar valid" ]]; then
  44         return 0;
  45     elif [[ "$returnFlag2" = "tar created" ]] && ! [[ "$returnFlag1" = "tar moved" ]]; then
  46         return 1; # tar missing so created
  47     elif [[ "$returnFlag2" = "tar created" ]] && [[ "$returnFlag1" = "tar moved" ]]; then
  48         return 2; # tar not readable so moved; replaced
  49     fi
  50 } # checks if arg1 is tar; creates one otherwise
  51 #===END Declare local script functions===
  52
  53 #====BEGIN sample code====
  54 #myFile="/tmp/$(date +%s)..tar"
  55 myFile="/tmp/$(date +%Y%m%d).tar"
  56 if [[ -f "$myFile" ]]; then yell "$myFile already exists."; else yell "$myFile doesn't yet exist."; fi
  57 if checkMakeTar "$myFile"; then
  58     yell "checkMakeTar() function run and exited:$?";
  59 else
  60     yell "checkMakeTar() function run and exited:$?";
  61 fi
  62
  63 if [[ -f "$myFile" ]]; then
  64     yell "Now exists    :$myFile";
  65     ls -l "$myFile";
  66 else
  67     yell "Does not exist:$myFile";
  68     ls -l "$myFile";
  69 fi
  70 #====END sample code====