unitproc/bkt-checkMakeTar

   1 #!/bin/bash
   2 # Desc: Checks that a valid tar archive exists, creates one otherwise
   3
   4 #===BEGIN Declare local script functions===
   5 yell() { echo "$0: $*" >&2; }      #o Yell, Die, Try Three-Fingered Claw technique
   6 die() { yell "$*"; exit 111; }     #o Ref/Attrib: https://stackoverflow.com/a/25515370
   7 try() { "$@" || die "cannot $*"; } #o
   8 checkMakeTar() {
   9     # Desc: Checks that a valid tar archive exists, creates one otherwise
  10     # Usage: checkMakeTar [ path ]
  11     # Version: 1.0.2
  12     # Input: arg1: path of tar archive
  13     # Output: exit code 0 : tar readable
  14     #         exit code 1 : tar missing; created
  15     #         exit code 2 : tar not readable; moved; replaced
  16     # Depends: bash 5, date 8, tar 1, try()
  17     local pathTar returnFlag0 returnFlag1 returnFlag2
  18     pathTar="$1";
  19
  20     # Check if file is a valid tar archive
  21     if tar --list --file="$pathTar" 1>/dev/null 2>&1; then
  22         ## T1: return success
  23         returnFlag0="tar valid";
  24     else
  25         ## F1: Check if file exists
  26         if [[ -f "$pathTar" ]]; then
  27             ### T: Rename file
  28             try mv "$pathTar" "$pathTar""--broken--""$(date +%Y%m%dT%H%M%S)" && \
  29                 returnFlag1="tar moved";
  30         else
  31             ### F: -
  32             :
  33         fi;
  34         ## F2: Create tar archive, return 0
  35         try tar --create --file="$pathTar" --files-from=/dev/null && \
  36             returnFlag2="tar created";
  37     fi;
  38
  39     # Determine function return code
  40     if [[ "$returnFlag0" = "tar valid" ]]; then
  41         return 0;
  42     elif [[ "$returnFlag2" = "tar created" ]] && ! [[ "$returnFlag1" = "tar moved" ]]; then
  43         return 1; # tar missing so created
  44     elif [[ "$returnFlag2" = "tar created" ]] && [[ "$returnFlag1" = "tar moved" ]]; then
  45         return 2; # tar not readable so moved; replaced
  46     fi;
  47 } # checks if arg1 is tar; creates one otherwise
  48 #===END Declare local script functions===
  49
  50 #====BEGIN sample code====
  51 #myFile="/tmp/$(date +%s)..tar"
  52 myFile="/tmp/$(date +%Y%m%d).tar"
  53 if [[ -f "$myFile" ]]; then yell "$myFile already exists."; else yell "$myFile doesn't yet exist."; fi
  54 if checkMakeTar "$myFile"; then
  55     yell "checkMakeTar() function run and exited:$?";
  56 else
  57     yell "checkMakeTar() function run and exited:$?";
  58 fi
  59
  60 if [[ -f "$myFile" ]]; then
  61     yell "Now exists    :$myFile";
  62     ls -l "$myFile";
  63 else
  64     yell "Does not exist:$myFile";
  65     ls -l "$myFile";
  66 fi
  67 #====END sample code====
  68
  69 # Author: Steven Baltakatei Sandoval
  70 # License: GPLv3+