sysutils/tick_second.sh

   1 #!/bin/bash
   2
   3 # Desc: Outputs to stdout the current iso-8601 timestamp (second accuracy)
   4 # Usage: tick_second.sh
   5 # Example tick_second.sh
   6
   7 #==BEGIN Define script parameters==
   8 #===BEGIN Declare variables===
   9 declare -Ag appRollCall # Associative array for storing app status
  10 declare -Ag fileRollCall # Associative array for storing file status
  11 declare -Ag dirRollCall # Associative array for storing dir status
  12 declare exitFlag
  13 #===END Declare variables===
  14
  15
  16 #===BEGIN Declare local script functions===
  17 yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
  18 die() { yell "$*"; exit 111; }
  19 try() { "$@" || die "cannot $*"; }
  20 checkapp() {
  21     # Desc: If arg is a command, save result in assoc array 'appRollCall'
  22     # Usage: checkapp arg1 arg2 arg3 ...
  23     # Version: 0.1.1
  24     # Input: global assoc. array 'appRollCall'
  25     # Output: adds/updates key(value) to global assoc array 'appRollCall'
  26     # Depends: bash 5.0.3
  27     local returnState
  28
  29     #===Process Args===
  30     for arg in "$@"; do
  31         if command -v "$arg" 1>/dev/null 2>&1; then # Check if arg is a valid command
  32             appRollCall[$arg]="true";
  33             if ! [ "$returnState" = "false" ]; then returnState="true"; fi;
  34         else
  35             appRollCall[$arg]="false"; returnState="false";
  36         fi;
  37     done;
  38
  39     #===Determine function return code===
  40     if [ "$returnState" = "true" ]; then
  41         return 0;
  42     else
  43         return 1;
  44     fi;
  45 } # Check that app exists
  46 displayMissing() {
  47     # Desc: Displays missing apps, files, and dirs
  48     # Usage: displayMissing
  49     # Version 0.1.1
  50     # Input: associative arrays: appRollCall, fileRollCall, dirRollCall
  51     # Output: stderr: messages indicating missing apps, file, or dirs
  52     # Depends: bash 5, checkAppFileDir()
  53     local missingApps value appMissing missingFiles fileMissing
  54     local missingDirs dirMissing
  55
  56     #==BEGIN Display errors==
  57     #===BEGIN Display Missing Apps===
  58     missingApps="Missing apps  :";
  59     #for key in "${!appRollCall[@]}"; do echo "DEBUG:$key => ${appRollCall[$key]}"; done
  60     for key in "${!appRollCall[@]}"; do
  61         value="${appRollCall[$key]}";
  62         if [ "$value" = "false" ]; then
  63             #echo "DEBUG:Missing apps: $key => $value";
  64             missingApps="$missingApps""$key ";
  65             appMissing="true";
  66         fi;
  67     done;
  68     if [ "$appMissing" = "true" ]; then  # Only indicate if an app is missing.
  69         echo "$missingApps" 1>&2;
  70     fi;
  71     unset value;
  72     #===END Display Missing Apps===
  73
  74     #===BEGIN Display Missing Files===
  75     missingFiles="Missing files:";
  76     #for key in "${!fileRollCall[@]}"; do echo "DEBUG:$key => ${fileRollCall[$key]}"; done
  77     for key in "${!fileRollCall[@]}"; do
  78         value="${fileRollCall[$key]}";
  79         if [ "$value" = "false" ]; then
  80             #echo "DEBUG:Missing files: $key => $value";
  81             missingFiles="$missingFiles""$key ";
  82             fileMissing="true";
  83         fi;
  84     done;
  85     if [ "$fileMissing" = "true" ]; then  # Only indicate if an app is missing.
  86         echo "$missingFiles" 1>&2;
  87     fi;
  88     unset value;
  89     #===END Display Missing Files===
  90
  91     #===BEGIN Display Missing Directories===
  92     missingDirs="Missing dirs:";
  93     #for key in "${!dirRollCall[@]}"; do echo "DEBUG:$key => ${dirRollCall[$key]}"; done
  94     for key in "${!dirRollCall[@]}"; do
  95         value="${dirRollCall[$key]}";
  96         if [ "$value" = "false" ]; then
  97             #echo "DEBUG:Missing dirs: $key => $value";
  98             missingDirs="$missingDirs""$key ";
  99             dirMissing="true";
 100         fi;
 101     done;
 102     if [ "$dirMissing" = "true" ]; then  # Only indicate if an dir is missing.
 103         echo "$missingDirs" 1>&2;
 104     fi;
 105     unset value;
 106     #===END Display Missing Directories===
 107
 108     #==END Display errors==
 109 } # Display missing apps, files, dirsw
 110 main() {
 111     # Desc: main program
 112     # Input: var: arg1:        path
 113     #        var: appRollCall  checkapp() dependency
 114     #        var: exitFlag     indicates to script if exit required
 115     # Output: stdout: iso-8601 date string
 116     # Depends: try()
 117
 118     # Validate input
 119     ## Check argument count (must be 0)
 120     if [[ $# -gt 0 ]]; then yell "ERROR:Too many arguments:$#"; exitFlag="true"; fi;
 121
 122     ## Check Apps
 123     if ! checkapp date echo; then yell "ERROR:Missing App"; exitFlag="true"; fi;
 124
 125     ## Report errors
 126     displayMissing;
 127     if [[ $exitFlag == "true" ]]; then exit 1; fi;
 128
 129     # Form output
 130     output="$(date +%Y-%m-%dT%H:%M:%S%z)"; #iso-8601 string (e.g. 2021-05-28T19:30:57+0000)
 131
 132     # Write output
 133     echo "$output";
 134 }
 135
 136 #===END Declare local script functions===
 137 #==END Define script parameters==
 138
 139 try main "$@";