unitproc/bktemplate

   1 #!/bin/bash
   2
   3 # Author: Steven Baltakatei Sandoval
   4 # Description: Template for bash scripts.
   5 # Note: Use hide-show-block function to aid readability. (ex: https://www.emacswiki.org/emacs/HideShow ).
   6
   7 #==BEGIN Variable Initialization==
   8
   9 #===BEGIN Global constants===
  10 SCRIPT_TTL=10                   # Limit script life to this in seconds.
  11 PATH="/usr/local/bin/:$PATH"    # Add user binary executable directory to PATH.
  12 PATH="/opt/bktei:$PATH"         # Add 'optional' executable directory to PATH.
  13 SCRIPT_HOSTNAME=$(hostname)     # Save hostname of system running this script.
  14 SCRIPT_VERSION="bktemplate.sh 0.0.0" # Define version of script. Used by function 'showVersion'.
  15 SCRIPT_TIME_SHORT="$(date +%Y%m%dT%H%M%S%z)" # Save current date & time in ISO-8601 format (YYYYmmddTHHMMSS+zzzz).
  16 SCRIPT_DATE_SHORT="$(date +%Y%m%d)"          # Save current date in ISO-8601 format.
  17 #===END Global constants===
  18
  19 #===BEGIN Define script parameters
  20 declare -Ag appRollCall # Associative array for storing app status (function checkapp())
  21 declare -Ag fileRollCall # Associative array for storing file status (function checkfile())
  22 #===END Define script parameters
  23 #==END Variable Initialization==
  24
  25 #==BEGIN Function Definitions==
  26 yell() { echo "$0: $*" >&2; } # Yell, Die, Try Three-Fingered Claw technique; # Ref/Attrib: https://stackoverflow.com/a/25515370
  27 die() { yell "$*"; exit 111; }
  28 try() { "$@" || die "cannot $*"; }
  29
  30 echoerr() {
  31     # Usage: echo [ arguments ]
  32     # Description: Prints provided arguments to stderr.
  33     # Input: unspecified
  34     # Output: stderr
  35     # Script function dependencies: none
  36     # External function dependencies: echo
  37     # Last modified: 2020-04-11T21:16Z
  38     # Last modified by: Steven Baltakatei Sandoval
  39     # License: GPLv3+
  40     # Ref./Attrib:
  41     #  [1]: # Roth, James (2010-06-07). ["How to print text to stderr instead of stdout"](https://stackoverflow.com/a/2990533). Licensed CC BY-SA 4.0.
  42
  43     echo "$@" 1>&2; # Define stderr echo function. See [1].
  44     return 0; # Function finished.
  45 } # Define stderr message function.
  46 vbm() {
  47     # Usage: vbm "DEBUG:verbose message here"
  48     # Description: Prints verbose message ("vbm") to stderr if OPTION_VERBOSE is set to "true".
  49     # Input:
  50     #   - OPTION_VERBOSE  variable set by processArguments function. (ex: "true", "false")
  51     #   - "$@"            positional arguments fed to this function.
  52     # Output: stderr
  53     # Script function dependencies: echoerr
  54     # External function dependencies: echo
  55     # Last modified: 2020-04-11T23:57Z
  56     # Last modified by: Steven Baltakatei Sandoval
  57     # License: GPLv3+
  58     # Ref./Attrib:
  59
  60     if [ "$OPTION_VERBOSE" = "true" ]; then
  61         FUNCTION_TIME=$(date --iso-8601=ns); # Save current time in nano seconds.
  62         echoerr "[$FUNCTION_TIME] ""$*"; # Display argument text.
  63     fi
  64
  65     # End function
  66     return 0; # Function finished.
  67 } # Verbose message display function.
  68 run() {
  69     # Usage: run [cmd]
  70     # Description: Runs command; reports success if command exit code 0; exits otherwise.
  71     # Input: none
  72     # Output: stdout
  73     # Script function dependencies: none
  74     # Last modified: 2020-06-19T22:09Z
  75     # Last modified by: Steven Baltakatei Sandoval
  76     # License: GPLv3+
  77     # Ref.Attrib: https://stackoverflow.com/a/18880585
  78     cmd_output=$(eval $1)
  79     return_value=$?
  80     if [ $return_value != 0 ]; then
  81         echo "Command $1 failed";
  82         exit -1;
  83     else
  84         echo "output: $cmd_output";
  85         echo "Command succeeded.";
  86     fi
  87     return $return_value
  88 } #
  89 showUsage() {
  90     # Usage: showUsage
  91     # Description: Displays script usage information.
  92     # Input: none
  93     # Output: stderr
  94     # Script function dependencies: echoerr
  95     # External dependencies: bash (5.0.3), echo
  96     # Last modified: 2020-05-04T16:11Z
  97     # Last modified by: Steven Baltakatei Sandoval
  98     # License: GPLv3+
  99     # Ref./Attrib.:
 100
 101     echoerr "USAGE:"
 102     echoerr "    bktemplate.sh [ options ]"
 103     echoerr
 104     echoerr "OPTIONS:"
 105     echoerr "    -h, --help"
 106     echoerr "            Display help information."
 107     echoerr
 108     echoerr "    --version"
 109     echoerr "            Display script version."
 110     echoerr
 111     echoerr "    -v, --verbose"
 112     echoerr "            Display debugging info."
 113     echoerr
 114     echoerr "    -o, --output-file [ file ]"
 115     echoerr "            Specify output file."
 116     echoerr
 117     echoerr "    -i, --input-file [ file ]"
 118     echoerr "            Specify input file."
 119     echoerr
 120     echoerr "    -o, --output-dir [ directory ]"
 121     echoerr "            Specify output directory."
 122     echoerr
 123     echoerr "    -i, --input-dir [ directory ]"
 124     echoerr "            Specify input directory."
 125     echoerr
 126
 127     # End function
 128     return 0; # Function finished.
 129 } # Display information on how to use this script.
 130 showVersion() {
 131     # Usage: showVersion
 132     # Descriptoin: Displays script version and license information.
 133     # Input: unspecified
 134     # Output: stderr
 135     # Script function dependencies: echoerr
 136     # External function dependencies: echo
 137     # Last modified: 2020-04-11T23:57Z
 138     # Last modified by: Steven Baltakatei Sandoval
 139     # License: GPLv3+
 140     # Ref./Attrib:
 141
 142     # Initialize function
 143     vbm "DEBUG:showVersion function called."
 144
 145     # Perform work
 146     OUTPUT="$SCRIPT_VERSION"
 147
 148     # Display results
 149     echoerr "$OUTPUT";
 150
 151     # End function
 152     vbm "DEBUG:showVersion function ended."
 153     return 0; # Function finished.
 154 } # Display script version.
 155 processArguments() {
 156     # Usage: processArguments "$@"
 157     # Description: Processes provided arguments in order to set script option variables useful for
 158     #   changing how other functions behave. For example, it may:
 159     #   1. Activate verbose mode
 160     # Input: "$@"          (list of arguments provided to the function)
 161     # Output: Sets following variables used by other functions:
 162     #   OPTION_VERBOSE     Indicates verbose mode enable status.  (ex: "true", "false")
 163     #   DIROUT1            Path to output directory.
 164     #   FILEOUT1           Path to output file.
 165     #   DIRIN1             Path to input directory.
 166     #   FILEIN1            Path to input file.
 167     #   OPTION_FILEOUT1_OVERWRITE Indicates whether file FILEOUT1 should be overwritten (ex: "true", "false')
 168     # Script function dependencies:
 169     #   - echoerr          Displays messages to stderr.
 170     #   - vbm              Displays messsages to stderr if OPTION_VERBOSE set to "true".
 171     # External dependencies: bash (5.0.3), echo
 172     # Last modified: 2020-05-04T14:41Z
 173     # Last modified by: Steven Baltakatei Sandoval
 174     # License: GPLv3+
 175     # Ref./Attrib.:
 176     #  [1]: Marco Aurelio (2014-05-08). "echo that outputs to stderr". https://stackoverflow.com/a/23550347
 177
 178     # Initialize function
 179     #vbm "DEBUG:processArguments function called."
 180
 181     # Perform work
 182     while [ ! $# -eq 0 ]; do   # While number of arguments ($#) is not (!) equal to (-eq) zero (0).
 183         #1>&2 echo "DEBUG:Starting processArguments while loop." # Debug stderr message. See [1].
 184         #1>&2 echo "DEBUG:Provided arguments are:""$*" # Debug stderr message. See [1].
 185         case "$1" in
 186             -h | --help) showUsage; exit 1;; # Display usage.
 187             --version) showVersion; exit 1;; # Show version
 188             -v | --verbose) OPTION_VERBOSE="true"; vbm "DEBUG:Verbose mode enabled.";; # Enable verbose mode. See [1].
 189             -i | --input-file) # Define input file path
 190                 if [ -f "$2" ]; then # If $2 is file that exists, set FILEIN1 to $2, pop $2.
 191                     FILEIN1="$2";
 192                     shift;
 193                     vbm "DEBUG:Input file FILEIN1 set to:""$2";
 194                 else
 195                     echoerr "ERROR: Specified input file does not exist:""$2";
 196                     echoerr "Exiting.";
 197                     exit 1;
 198                 fi ;;
 199             -I | --input-dir) # Define input directory path
 200                 if [ -d "$2" ]; then # If $2 is dir that exists, set DIRIN1 to $2, pop $2.
 201                     DIRIN1="$2";
 202                     shift;
 203                     vbm "DEBUG:Input directory DIRIN1 set to:""$2";
 204                 else # Display error if $2 is not a valid dir.
 205                     echoerr "ERROR:Specified input directory does not exist:""$2";
 206                     echoerr "Exiting.";
 207                     exit 1;
 208                 fi ;;
 209             -o | --output-file) # Define output file path
 210                 if [ -f "$2" ]; then # If $2 is file that exists, prompt user to continue to overwrite, set FILEOUT1 to $2, pop $2.
 211                     echoerr "Specified output file $2 already exists. Overwrite? (y/n):"
 212                     read m; case $m in
 213                                 y | Y | yes) OPTION_FILEOUT1_OVERWRITE="true";;
 214                                 n | N | no) OPTION_FILEOUT1_OVERWRITE="false";;
 215                                 *) echoerr "Invalid selection. Exiting."; exit 1;;
 216                             esac
 217                     if [ "$OPTION_FILEOUT1_OVERWRITE" == "true" ]; then
 218                         FILEOUT1="$2";
 219                         shift;
 220                         vbm "DEBUG:Output file FILEOUT1 set to:""$2";
 221                     else
 222                         echoerr "ERORR:Exiting in order to not overwrite output file:""$FILEOUT1";
 223                         exit 1;
 224                     fi
 225                 else
 226                     FILEOUT1="$2";
 227                     shift;
 228                     vbm "DEBUG:Output file FILEOUT1 set to:""$2";
 229                 fi ;;
 230             -O | --output-dir) # Define output directory path
 231                 if [ -d "$2" ]; then # If $2 is dir that exists, set DIROUT1 to $2, pop $2
 232                     DIROUT1="$2";
 233                     shift;
 234                     vbm "DEBUG:Output directory DIROUT1 set to:""$2";
 235                 else
 236                     echoerr "ERROR:Specified output directory is not valid:""$2";
 237                     echoerr "Exiting.";
 238                     exit 1;
 239                 fi ;;
 240             *) echoerr "ERROR: Unrecognized argument."; exit 1;; # Handle unrecognized options. See [1].
 241         esac
 242         shift
 243     done
 244
 245     # End function
 246     vbm "DEBUG:processArguments function ended."
 247     return  0; # Function finished.
 248 } # Evaluate script options from positional arguments (ex: $1, $2, $3, etc.).
 249 checkExecutables() {
 250     # Usage: checkExecutables [ command1 ] [ command2 ] [...] [ commandN ]
 251     # Description: Checks that provided commands exist and displays those that do not exist.
 252     # Input:
 253     #   - command names (arguments)
 254     # Output: commands that don't exist (stderr)
 255     # Script function dependencies:
 256     #   - echoerr          for displaying errors via stderr
 257     #   - processArguments for setting OPTION_VERBOSE
 258     #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
 259     # External dependencies: bash (5.0.3), command
 260     # Last modified: 2020-04-11T23:59Z
 261     # Last modified by: Steven Baltakatei Sandoval
 262     # License: GPLv3+
 263     # Ref./Attrib.:
 264     #  [1]: SiegeX (2010-12-12). ["Difference between return and exit in Bash functions."](https://stackoverflow.com/a/4419971). Licensed CC BY-SA 4.0.
 265     #  [2]: Darryl Hein (2009-12-23). ["Add a new element to an array without specifying the index in Bash"](https://stackoverflow.com/a/1951523). Licensed CC BY-SA 4.0.
 266     #  [3]: kojiro (2012-10-03). ["Convert command line arguments into an array in Bash"](https://stackoverflow.com/a/12711853)
 267     #  [4]: niieani (2016-01-12). ["How to copy an array in Bash?"](https://stackoverflow.com/a/34733375/10850071). Licensed CC BY-SA 4.0.
 268
 269     # Initialize function
 270     vbm "DEBUG:checkExecutables function called."
 271     declare -a candidateCommandsNames # Initialize array for storing positional arguments provided to this function.
 272     candidateCommandsNames=("$@") # Save positional arguments to variable as string. See [3].
 273     vbm "DEBUG:candidateCommandsNames:""$*"
 274     vbm "DEBUG:candidateCommandsNames[0]:""${candidateCommandsNames[0]}"
 275     vbm "DEBUG:candidateCommandsNames[1]:""${candidateCommandsNames[1]}"
 276     vbm "DEBUG:candidateCommandsNames[2]:""${candidateCommandsNames[2]}"
 277     declare -a outputInvalidCommandsArray # Initialize arary for storing names of invalid commands.
 278     declare -a outputValidCommandsArray # Initialize array for storing names of valid commands.
 279
 280     # Perform work
 281     for candidateCommandName in "${candidateCommandsNames[@]}"; do  # Search through all space-delimited text for valid commands.
 282         if command -v "$candidateCommandName" 1>/dev/null 2>/dev/null; then # Check if a command is valid or not.
 283             outputValidCommandsArray+=("$candidateCommandName") ; # See [2].
 284             vbm "DEBUG:Adding $candidateCommandName to outputValidCommandsArray."
 285         else
 286             outputInvalidCommandsArray+=("$candidateCommandName") ; # See [2].
 287             vbm "DEBUG:Adding $candidateCommandName to outputInvalidCommandsArray."
 288         fi
 289     done
 290
 291     # Output results
 292     if [ ${#outputInvalidCommandsArray[@]} -gt 0 ]; then # if number of elements in outputInvalidCommandsArray greater than 0, then display offending commands and exit 1.
 293         echoerr "ERROR: Invalid commands found:""${outputInvalidCommandsArray[@]}"; # display invalid commands as error
 294         exit 1; # See [1].
 295     elif [ ${#outputInvalidCommandsArray[@]} -eq 0 ]; then # if number of elements in outputInvalidCommandsArray equals zero, then return 0.
 296         vbm "DEBUG: Valid commands are:""${outputValidCommandsArray[@]}"; # display valid commands if verbose mode enabled
 297         return 0; # See [1].
 298     else
 299         echoerr "ERROR: Check outputInvalidCommandsArray.";
 300     fi
 301
 302     # End function
 303     vbm "DEBUG:checkExecutables function ended."
 304     return 0; # Function finished.
 305 } # Check that certain executables exist.
 306 updateTimeConstants() {
 307     # Usage: updateTimeConstants
 308     # Description: Updates time-related variables for use by other scripts.
 309     # Input: (none)
 310     # Output: Sets following variables:
 311     #   TIME_CURRENT       Current time in long ISO-8601 format.  (ex: YYYY-mm-ddTHH:MM:SS+ZZZZ)
 312     #   TIME_CURRENT_SHORT Current time in short ISO-8601 format. (ex: YYYYmmddTHHMMSS+ZZZZ)
 313     #   DATE_CURRENT       Current date in ISO-8601 format.       (ex: YYYY-mm-dd)
 314     #   DATE_CURRENT_SHORT Current date in short ISO-8601 format. (ex: YYYYmmdd)
 315     #   DATE_TOMORROW      Tomorrow's date in ISO-8601 format.    (ex: YYYY-mm-dd)
 316     #   TIME_NEXT_MIDNIGHT Time of tomorrow's midnight in long    (ex: YYYY-mm-ddTHH:MM:SS+ZZZZ)
 317     #                       ISO-861 format.
 318     #   SEC_TIL_MIDNIGHT   Seconds until next midnight.
 319     # Script function dependencies:
 320     #   - echoerr          for displaying errors via stderr
 321     #   - processArguments for setting OPTION_VERBOSE
 322     #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
 323     # External dependencies: bash (5.0.3), date, echo
 324     # Last modified: 2020-04-11T23:59Z
 325     # Last modified by: Steven Baltakatei Sandoval
 326     # License: GPLv3+
 327     # Ref./Attrib.:
 328
 329     # Initialize function
 330     vbm "DEBUG:updateTimeConstants function called."
 331
 332     # Perform work
 333     TIME_CURRENT="$(date --iso-8601=seconds)" ;
 334     TIME_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%dT%H%M%S%z)"
 335     DATE_CURRENT="$(date -d "$TIME_CURRENT" --iso-8601=date)" ;
 336     DATE_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%d)" ;
 337     DATE_TOMORROW="$(date -d "$TIME_CURRENT next day" --iso-8601=date)" ;
 338     TIME_NEXT_MIDNIGHT="$(date -d "$DATE_TOMORROW" --iso-8601=seconds)" ;
 339     SECONDS_UNTIL_NEXT_MIDNIGHT="$((  $(date +%s -d "$TIME_NEXT_MIDNIGHT") - $(date +%s -d "$TIME_CURRENT")  ))" ;
 340
 341     # End function
 342     vbm "DEBUG:updateTimeConstants function ended."
 343     return 0; # Function finished.
 344 } # Update time constants
 345 checkapp() {
 346     # Desc: If arg is a command, save result in assoc array 'appRollCall'
 347     # Usage: checkapp arg1 arg2 arg3 ...
 348     # Input: global assoc. array 'appRollCall'
 349     # Output: adds/updates key(value) to global assoc array 'appRollCall'
 350     local returnState
 351     #echo "DEBUG:$(date +%S.%N)..Starting checkapp function."
 352     #echo "DEBUG:args: $*"
 353     #echo "DEBUG:returnState:$returnState"
 354
 355     #===Process Args===
 356     for arg in "$@"; do
 357         #echo "DEBUG:processing arg:$arg"
 358         if command -v "$arg" 1>/dev/null 2>&1; then # Check if arg is a valid command
 359             appRollCall[$arg]="true";
 360             #echo "DEBUG:appRollCall[$arg]:"${appRollCall[$arg]}
 361             if ! [ "$returnState" = "false" ]; then returnState="true"; fi
 362         else
 363             appRollCall[$arg]="false"; returnState="false";
 364         fi
 365     done
 366
 367     #for key in "${!appRollCall[@]}"; do echo "DEBUG:$key => ${appRollCall[$key]}"; done
 368     #echo "DEBUG:evaluating returnstate. returnState:"$returnState
 369
 370     #===Determine function return code===
 371     if [ "$returnState" = "true" ]; then
 372         #echo "DEBUG:checkapp returns true for $arg";
 373         return 0;
 374     else
 375         #echo "DEBUG:checkapp returns false for $arg";
 376         return 1;
 377     fi
 378 } # Check that app exists
 379 checkfile() {
 380     # Desc: If arg is a file path, save result in assoc array 'fileRollCall'
 381     # Usage: checkfile arg1 arg2 arg3 ...
 382     # Input: global assoc. array 'fileRollCall'
 383     # Output: adds/updates key(value) to global assoc array 'fileRollCall';
 384     # Output: returns 0 if app found, 1 otherwise
 385     local returnState
 386
 387     #===Process Args===
 388     for arg in "$@"; do
 389         #echo "DEBUG:processing arg:$arg"
 390         if [ -f "$arg" ]; then
 391             fileRollCall["$arg"]="true";
 392             #echo "DEBUG:fileRollCall[\"$arg\"]:"${fileRollCall["$arg"]}
 393             if ! [ "$returnState" = "false" ]; then returnState="true"; fi
 394         else
 395             fileRollCall["$arg"]="false"; returnState="false";
 396         fi
 397     done
 398
 399     #for key in "${!fileRollCall[@]}"; do echo "DEBUG:fileRollCall key [$key] is:${fileRollCall[$key]}"; done
 400     #echo "DEBUG:evaluating returnstate. returnState:"$returnState
 401
 402     #===Determine function return code===
 403     if [ "$returnState" = "true" ]; then
 404         #echo "DEBUG:checkapp returns true for $arg";
 405         return 0;
 406     else
 407         #echo "DEBUG:checkapp returns false for $arg";
 408         return 1;
 409     fi
 410 } # Check that file exists
 411 main() {
 412     # Usage: main "$@"    # See [1].
 413     # Input: unspecified (note: all Global Constants declared at beginning of script assumed to be available)
 414     #   OPTION_VERBOSE   (used by vbm, set by processArguments)  (ex: "true", "false")
 415     # Output: unspecified
 416     # Script function dependencies:
 417     #   - echoerr          for displaying errors via stderr
 418     #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
 419     #   - processArguments for setting OPTION_VERBOSE
 420     #   - checkExecutables for checking that specified commands are available
 421     # External dependencies: bash (5.0.3), echo
 422     # Last modified: 2020-05-04T16:50Z
 423     # Last modified by: Steven Baltakatei Sandoval
 424     # License: GPLv3+
 425     # Ref./Attrib.:
 426     #  [1]: ErichBSchulz (2011-11-20). [How to correctly pass bash script arguments to functions](https://stackoverflow.com/a/8198970). Licensed CC BY-SA 4.0.
 427
 428     # Initialize function
 429     processArguments "$@" # Process arguments.
 430     vbm "DEBUG:main function called."
 431     vbm "DEBUG:main function arguments are:""$@"
 432     checkExecutables "echo" "date" "cut" "awk" # Confirm that executables necessary to run are available. Exit if any fail.
 433
 434     # Process inputs
 435     if [ -v FILEIN1 ]; then # VERBOSE: Display contents of FILEIN1 if FILEIN1 has been set.
 436         vbm "DEBUG:main function detects input file:""$FILEIN1" ;
 437         vbm "DEBUG:contents of following file is displayed below:""$FILEIN1" ;
 438         if [ "$OPTION_VERBOSE" == "true" ]; then # display FILEIN1 contents via cat if verbose mode specified
 439             echoerr "========""$FILEIN1"" START""========" ;
 440             cat "$FILEIN1" 1>&2 ;
 441             echoerr "========""$FILEIN1"" END""========" ;
 442         fi
 443     fi
 444
 445     # Perform work
 446     OUTPUT="$OUTPUT""Hello world.\n"
 447     if [ -v FILEIN1 ]; then
 448         OUTPUT="$OUTPUT""The b2sum hash of $FILEIN1 is: $(b2sum "$FILEIN1" | awk '{print $1}').\n";
 449     fi
 450     OUTPUT="$OUTPUT""The current time is:""$SCRIPT_TIME_SHORT\n"
 451
 452     # Output results
 453     echo -e "$OUTPUT"
 454
 455     if [ -v FILEOUT1 ]; then  # if FILEOUT1 set, write to this file.
 456         vbm "DEBUG:main function detects output file:""$FILEOUT1" ;
 457         echo -e "$OUTPUT" > "$FILEOUT1" ;
 458         vbm "DEBUG:main funtion wrote OUTPUT to:""$FILEOUT1" ;
 459     elif [ -v DIROUT1 ]; then  # else if DIROUT1 set, set FILEOUT1 to timestamped filename, combine into PATHOUT1, write output to PATHOUT1.
 460         vbm "DEBUG:main function detects output directory:""$DIROUT1" ;
 461         FILEOUT1="$SCRIPT_TIME_SHORT"..output
 462         PATHOUT1="$DIROUT1"/"$FILEOUT1"
 463         echo -e "$OUTPUT" > $PATHOUT1 ;
 464         vbm "DEBUG:main function wrote output file to:""$PATHOUT1" ;
 465     fi
 466
 467     # End function
 468     vbm "DEBUG:main function ended."
 469     return 0; # Function finished.
 470 } # Main function
 471 #==END Function Definitions==
 472
 473 #==BEGIN Perform work and exit==
 474 main "$@" # Run main function.
 475 exit 0;
 476 #==END Perform work and exit==