unitproc/bktemp-checkMakeTar

   1 #!/bin/bash
   2
   3 # Desc: Checks that a valid tar archive exists, creates one otherwise
   4
   5 #===BEGIN Declare local script functions===
   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 checkMakeTar() {
  10     # Desc: Checks that a valid tar archive exists, creates one otherwise
  11     # Usage: checkMakeTar [ path ]
  12     # Version: 1.0.1
  13     # Input: arg1: path of tar archive
  14     # Output: exit code 0 : tar readable
  15     #         exit code 1 : tar missing; created
  16     #         exit code 2 : tar not readable; moved; replaced
  17     # Depends: try, tar, date
  18     local PATH_TAR returnFlag0 returnFlag1 returnFlag2
  19     PATH_TAR="$1"
  20
  21     # Check if file is a valid tar archive
  22     if tar --list --file="$PATH_TAR" 1>/dev/null 2>&1; then
  23         ## T1: return success
  24         returnFlag0="tar valid";
  25     else
  26         ## F1: Check if file exists
  27         if [[ -f "$PATH_TAR" ]]; then
  28             ### T: Rename file
  29             try mv "$PATH_TAR" "$PATH_TAR""--broken--""$(date +%Y%m%dT%H%M%S)" && \
  30                 returnFlag1="tar moved";
  31         else
  32             ### F: -
  33             :
  34         fi
  35         ## F2: Create tar archive, return 0
  36         try tar --create --file="$PATH_TAR" --files-from=/dev/null && \
  37             returnFlag2="tar created";
  38     fi
  39
  40     # Determine function return code
  41     if [[ "$returnFlag0" = "tar valid" ]]; then
  42         return 0;
  43     elif [[ "$returnFlag2" = "tar created" ]] && ! [[ "$returnFlag1" = "tar moved" ]]; then
  44         return 1; # tar missing so created
  45     elif [[ "$returnFlag2" = "tar created" ]] && [[ "$returnFlag1" = "tar moved" ]]; then
  46         return 2; # tar not readable so moved; replaced
  47     fi
  48 } # checks if arg1 is tar; creates one otherwise
  49 #===END Declare local script functions===
  50
  51 #====BEGIN sample code====
  52 #myFile="/tmp/$(date +%s)..tar"
  53 myFile="/tmp/$(date +%Y%m%d).tar"
  54 if [[ -f "$myFile" ]]; then yell "$myFile already exists."; else yell "$myFile doesn't yet exist."; fi
  55 if checkMakeTar "$myFile"; then
  56     yell "checkMakeTar() function run and exited:$?";
  57 else
  58     yell "checkMakeTar() function run and exited:$?";
  59 fi
  60
  61 if [[ -f "$myFile" ]]; then
  62     yell "Now exists    :$myFile";
  63     ls -l "$myFile";
  64 else
  65     yell "Does not exist:$myFile";
  66     ls -l "$myFile";
  67 fi
  68 #====END sample code====
  69
  70 # Author: Steven Baltakatei Sandoval
  71 # License: GPLv3+