X-Git-Url: https://zdv2.bktei.com/gitweb/BK-2020-03.git/blobdiff_plain/dd9f30387a6f3e81b56ea3e86bef174422b37c77..fdf917e1ee70b612202fe10fab2e73d0ea077017:/unitproc/bktemplate.sh

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+#!/bin/bash
+
+# Date: 2020-05-04T16:50Z
+# Author: Steven Baltakatei Sandoval
+# Description: Template for bash scripts.
+# Note: Use hide-show-block function to aid readability. (ex: https://www.emacswiki.org/emacs/HideShow ).
+
+#== Variable Initialization ==
+
+#== Global constants ==
+SCRIPT_TTL=10                   # Limit script life to this in seconds.
+PATH="/usr/local/bin/:$PATH"    # Add user binary executable directory to PATH.
+PATH="/opt/bktei:$PATH"         # Add 'optional' executable directory to PATH.
+SCRIPT_HOSTNAME=$(hostname)     # Save hostname of system running this script.
+SCRIPT_VERSION="bktemplate.sh 0.0.0" # Define version of script. Used by function 'showVersion'.
+SCRIPT_TIME_SHORT="$(date +%Y%m%dT%H%M%S%z)" # Save current date & time in ISO-8601 format (YYYYmmddTHHMMSS+zzzz).
+SCRIPT_DATE_SHORT="$(date +%Y%m%d)"          # Save current date in ISO-8601 format.
+
+#== Function Definitions ==
+echoerr() {
+    # Usage: echo [ arguments ]
+    # Description: Prints provided arguments to stderr.
+    # Input: unspecified
+    # Output: stderr
+    # Script function dependencies: none
+    # External function dependencies: echo
+    # Last modified: 2020-04-11T21:16Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib:
+    #  [1]: # Roth, James (2010-06-07). ["How to print text to stderr instead of stdout"](https://stackoverflow.com/a/2990533). Licensed CC BY-SA 4.0.
+    
+    echo "$@" 1>&2; # Define stderr echo function. See [1].
+    return 0; # Function finished.
+} # Define stderr message function.
+vbm() {
+    # Usage: vbm "DEBUG:verbose message here"
+    # Description: Prints verbose message ("vbm") to stderr if OPTION_VERBOSE is set to "true".
+    # Input:
+    #   - OPTION_VERBOSE  variable set by processArguments function. (ex: "true", "false")
+    #   - "$@"            positional arguments fed to this function.
+    # Output: stderr
+    # Script function dependencies: echoerr
+    # External function dependencies: echo
+    # Last modified: 2020-04-11T23:57Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib:
+
+    if [ "$OPTION_VERBOSE" == "true" ]; then
+	FUNCTION_TIME=$(date --iso-8601=ns); # Save current time in nano seconds.
+	echoerr "[$FUNCTION_TIME] ""$@"; # Display argument text.
+    fi
+
+    # End function
+    return 0; # Function finished.
+} # Verbose message display function.
+showUsage() {
+    # Usage: showUsage
+    # Description: Displays script usage information.
+    # Input: none
+    # Output: stderr
+    # Script function dependencies: echoerr
+    # External dependencies: bash (5.0.3), echo
+    # Last modified: 2020-05-04T16:11Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib.:
+    
+    echoerr "USAGE:"
+    echoerr "    bktemplate.sh [ options ]"
+    echoerr
+    echoerr "OPTIONS:"
+    echoerr "    -h, --help"
+    echoerr "            Display help information."
+    echoerr
+    echoerr "    --version"
+    echoerr "            Display script version."
+    echoerr
+    echoerr "    -v, --verbose"
+    echoerr "            Display debugging info."
+    echoerr
+    echoerr "    -o, --output-file [ file ]"
+    echoerr "            Specify output file."
+    echoerr
+    echoerr "    -i, --input-file [ file ]"
+    echoerr "            Specify input file."
+    echoerr
+    echoerr "    -o, --output-dir [ directory ]"
+    echoerr "            Specify output directory."
+    echoerr
+    echoerr "    -i, --input-dir [ directory ]"
+    echoerr "            Specify input directory."
+    echoerr
+
+    # End function
+    return 0; # Function finished.
+} # Display information on how to use this script.
+showVersion() {
+    # Usage: showVersion
+    # Descriptoin: Displays script version and license information.
+    # Input: unspecified
+    # Output: stderr
+    # Script function dependencies: echoerr
+    # External function dependencies: echo
+    # Last modified: 2020-04-11T23:57Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib:
+
+    # Initialize function
+    vbm "DEBUG:showVersion function called."
+
+    # Perform work
+    OUTPUT="$SCRIPT_VERSION"
+
+    # Display results
+    echoerr "$OUTPUT";
+
+    # End function
+    vbm "DEBUG:showVersion function ended."
+    return 0; # Function finished.
+} # Display script version.
+processArguments() {
+    # Usage: processArguments "$@"
+    # Description: Processes provided arguments in order to set script option variables useful for
+    #   changing how other functions behave. For example, it may:
+    #   1. Activate verbose mode
+    # Input: "$@"          (list of arguments provided to the function)
+    # Output: Sets following variables used by other functions:
+    #   OPTION_VERBOSE     Indicates verbose mode enable status.  (ex: "true", "false")
+    #   DIROUT1            Path to output directory.
+    #   FILEOUT1           Path to output file.
+    #   DIRIN1             Path to input directory.
+    #   FILEIN1            Path to input file.
+    #   OPTION_FILEOUT1_OVERWRITE Indicates whether file FILEOUT1 should be overwritten (ex: "true", "false')
+    # Script function dependencies:
+    #   - echoerr          Displays messages to stderr.
+    #   - vbm              Displays messsages to stderr if OPTION_VERBOSE set to "true".
+    # External dependencies: bash (5.0.3), echo
+    # Last modified: 2020-05-04T14:41Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib.:
+    #  [1]: Marco Aurelio (2014-05-08). "echo that outputs to stderr". https://stackoverflow.com/a/23550347
+
+    # Initialize function
+    #vbm "DEBUG:processArguments function called."
+
+    # Perform work
+    while [ ! $# -eq 0 ]; do   # While number of arguments ($#) is not (!) equal to (-eq) zero (0).
+	#1>&2 echo "DEBUG:Starting processArguments while loop." # Debug stderr message. See [1].
+        #1>&2 echo "DEBUG:Provided arguments are:""$@" # Debug stderr message. See [1].
+	case "$1" in
+	    -h | --help) showUsage; exit 1;; # Display usage.
+	    --version) showVersion; exit 1;; # Show version
+	    -v | --verbose) OPTION_VERBOSE="true"; vbm "DEBUG:Verbose mode enabled.";; # Enable verbose mode. See [1].
+	    -i | --input-file) # Define input file path
+		if [ -f "$2" ]; then # If $2 is file that exists, set FILEIN1 to $2, pop $2.
+		    FILEIN1="$2";
+		    shift;
+		    vbm "DEBUG:Input file FILEIN1 set to:""$2";
+		else
+		    echoerr "ERROR: Specified input file does not exist:""$2";
+		    echoerr "Exiting.";
+		    exit 1;
+		fi ;; 
+	    -I | --input-dir) # Define input directory path
+		if [ -d "$2" ]; then # If $2 is dir that exists, set DIRIN1 to $2, pop $2.
+		    DIRIN1="$2";
+		    shift;
+		    vbm "DEBUG:Input directory DIRIN1 set to:""$2";
+		else # Display error if $2 is not a valid dir.
+		    echoerr "ERROR:Specified input directory does not exist:""$2";
+		    echoerr "Exiting.";
+		    exit 1;
+		fi ;; 
+	    -o | --output-file) # Define output file path
+		if [ -f "$2" ]; then # If $2 is file that exists, prompt user to continue to overwrite, set FILEOUT1 to $2, pop $2.
+		    echoerr "Specified output file $2 already exists. Overwrite? (y/n):"
+		    read m; case $m in
+				y | Y | yes) OPTION_FILEOUT1_OVERWRITE="true";;
+				n | N | no) OPTION_FILEOUT1_OVERWRITE="false";;
+				*) echoerr "Invalid selection. Exiting."; exit 1;;
+			    esac
+		    if [ "$OPTION_FILEOUT1_OVERWRITE" == "true" ]; then
+			FILEOUT1="$2";
+			shift;
+			vbm "DEBUG:Output file FILEOUT1 set to:""$2";
+		    else
+			echoerr "ERORR:Exiting in order to not overwrite output file:""$FILEOUT1";
+			exit 1;
+		    fi
+		else
+		    FILEOUT1="$2";
+		    shift;
+		    vbm "DEBUG:Output file FILEOUT1 set to:""$2";
+		fi ;;
+	    -O | --output-dir) # Define output directory path
+		if [ -d "$2" ]; then # If $2 is dir that exists, set DIROUT1 to $2, pop $2
+		    DIROUT1="$2";
+		    shift;
+		    vbm "DEBUG:Output directory DIROUT1 set to:""$2";
+		else
+		    echoerr "ERROR:Specified output directory is not valid:""$2";
+		    echoerr "Exiting.";
+		    exit 1;
+		fi ;; 
+	    *) echoerr "ERROR: Unrecognized argument."; exit 1;; # Handle unrecognized options. See [1].
+	esac
+	shift
+    done
+
+    # End function
+    vbm "DEBUG:processArguments function ended."
+    return  0; # Function finished.
+} # Evaluate script options from positional arguments (ex: $1, $2, $3, etc.).
+checkExecutables() {
+    # Usage: checkExecutables [ command1 ] [ command2 ] [...] [ commandN ]
+    # Description: Checks that provided commands exist and displays those that do not exist.
+    # Input:
+    #   - command names (arguments)
+    # Output: commands that don't exist (stderr)
+    # Script function dependencies:
+    #   - echoerr          for displaying errors via stderr
+    #   - processArguments for setting OPTION_VERBOSE
+    #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
+    # External dependencies: bash (5.0.3), command
+    # Last modified: 2020-04-11T23:59Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib.:
+    #  [1]: SiegeX (2010-12-12). ["Difference between return and exit in Bash functions."](https://stackoverflow.com/a/4419971). Licensed CC BY-SA 4.0.
+    #  [2]: Darryl Hein (2009-12-23). ["Add a new element to an array without specifying the index in Bash"](https://stackoverflow.com/a/1951523). Licensed CC BY-SA 4.0.
+    #  [3]: kojiro (2012-10-03). ["Convert command line arguments into an array in Bash"](https://stackoverflow.com/a/12711853)
+    #  [4]: niieani (2016-01-12). ["How to copy an array in Bash?"](https://stackoverflow.com/a/34733375/10850071). Licensed CC BY-SA 4.0.
+
+    # Initialize function
+    vbm "DEBUG:checkExecutables function called."
+    declare -a candidateCommandsNames # Initialize array for storing positional arguments provided to this function.
+    candidateCommandsNames=("$@") # Save positional arguments to variable as string. See [3].
+    vbm "DEBUG:candidateCommandsNames:""$@"
+    vbm "DEBUG:candidateCommandsNames[0]:""${candidateCommandsNames[0]}"
+    vbm "DEBUG:candidateCommandsNames[1]:""${candidateCommandsNames[1]}"
+    vbm "DEBUG:candidateCommandsNames[2]:""${candidateCommandsNames[2]}"
+    declare -a outputInvalidCommandsArray # Initialize arary for storing names of invalid commands.
+    declare -a outputValidCommandsArray # Initialize array for storing names of valid commands.
+
+    # Perform work
+    for candidateCommandName in "${candidateCommandsNames[@]}"; do  # Search through all space-delimited text for valid commands.
+	if command -v "$candidateCommandName" 1>/dev/null 2>/dev/null; then # Check if a command is valid or not.
+	    outputValidCommandsArray+=("$candidateCommandName") ; # See [2].
+	    vbm "DEBUG:Adding $candidateCommandName to outputValidCommandsArray."
+	else
+	    outputInvalidCommandsArray+=("$candidateCommandName") ; # See [2].
+	    vbm "DEBUG:Adding $candidateCommandName to outputInvalidCommandsArray."
+	fi
+    done
+
+    # Output results
+    if [ ${#outputInvalidCommandsArray[@]} -gt 0 ]; then # if number of elements in outputInvalidCommandsArray greater than 0, then display offending commands and exit 1.
+	echoerr "ERROR: Invalid commands found:""${outputInvalidCommandsArray[@]}"; # display invalid commands as error
+	exit 1; # See [1].
+    elif [ ${#outputInvalidCommandsArray[@]} -eq 0 ]; then # if number of elements in outputInvalidCommandsArray equals zero, then return 0.
+	vbm "DEBUG: Valid commands are:""${outputValidCommandsArray[@]}"; # display valid commands if verbose mode enabled
+	return 0; # See [1].
+    else
+	echoerr "ERROR: Check outputInvalidCommandsArray.";
+    fi
+
+    # End function
+    vbm "DEBUG:checkExecutables function ended."
+    return 0; # Function finished.
+} # Check that certain executables exist.
+updateTimeConstants() {
+    # Usage: updateTimeConstants
+    # Description: Updates time-related variables for use by other scripts.
+    # Input: (none)
+    # Output: Sets following variables:
+    #   TIME_CURRENT       Current time in long ISO-8601 format.  (ex: YYYY-mm-ddTHH:MM:SS+ZZZZ)
+    #   TIME_CURRENT_SHORT Current time in short ISO-8601 format. (ex: YYYYmmddTHHMMSS+ZZZZ)
+    #   DATE_CURRENT       Current date in ISO-8601 format.       (ex: YYYY-mm-dd)
+    #   DATE_CURRENT_SHORT Current date in short ISO-8601 format. (ex: YYYYmmdd)
+    #   DATE_TOMORROW      Tomorrow's date in ISO-8601 format.    (ex: YYYY-mm-dd)
+    #   TIME_NEXT_MIDNIGHT Time of tomorrow's midnight in long    (ex: YYYY-mm-ddTHH:MM:SS+ZZZZ)
+    #                       ISO-861 format.
+    #   SEC_TIL_MIDNIGHT   Seconds until next midnight.
+    # Script function dependencies:
+    #   - echoerr          for displaying errors via stderr
+    #   - processArguments for setting OPTION_VERBOSE
+    #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
+    # External dependencies: bash (5.0.3), date, echo
+    # Last modified: 2020-04-11T23:59Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib.:
+
+    # Initialize function
+    vbm "DEBUG:updateTimeConstants function called."
+
+    # Perform work
+    TIME_CURRENT="$(date --iso-8601=seconds)" ;
+    TIME_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%dT%H%M%S%z)"
+    DATE_CURRENT="$(date -d "$TIME_CURRENT" --iso-8601=date)" ;
+    DATE_CURRENT_SHORT="$(date -d "$TIME_CURRENT" +%Y%m%d)" ;
+    DATE_TOMORROW="$(date -d "$TIME_CURRENT next day" --iso-8601=date)" ;
+    TIME_NEXT_MIDNIGHT="$(date -d "$DATE_TOMORROW" --iso-8601=seconds)" ;
+    SECONDS_UNTIL_NEXT_MIDNIGHT="$((  $(date +%s -d "$TIME_NEXT_MIDNIGHT") - $(date +%s -d "$TIME_CURRENT")  ))" ;
+
+    # End function
+    vbm "DEBUG:updateTimeConstants function ended."
+    return 0; # Function finished.
+} # Update time constants
+
+#== Main Program Definition ==
+main() {
+    # Usage: main "$@"    # See [1].
+    # Input: unspecified (note: all Global Constants declared at beginning of script assumed to be available)
+    #   OPTION_VERBOSE   (used by vbm, set by processArguments)  (ex: "true", "false")
+    # Output: unspecified
+    # Script function dependencies:
+    #   - echoerr          for displaying errors via stderr
+    #   - vbm              for displaying verbose messages if OPTION_VERBOSE is "true"
+    #   - processArguments for setting OPTION_VERBOSE
+    #   - checkExecutables for checking that specified commands are available
+    # External dependencies: bash (5.0.3), echo
+    # Last modified: 2020-05-04T16:50Z
+    # Last modified by: Steven Baltakatei Sandoval
+    # License: GPLv3+
+    # Ref./Attrib.:
+    #  [1]: ErichBSchulz (2011-11-20). [How to correctly pass bash script arguments to functions](https://stackoverflow.com/a/8198970). Licensed CC BY-SA 4.0.
+
+    # Initialize function
+    processArguments "$@" # Process arguments.
+    vbm "DEBUG:main function called."
+    vbm "DEBUG:main function arguments are:""$@"
+    checkExecutables "echo" "date" "cut" "awk" # Confirm that executables necessary to run are available. Exit if any fail.
+
+    # Process inputs
+    if [ -v FILEIN1 ]; then # VERBOSE: Display contents of FILEIN1 if FILEIN1 has been set.
+	vbm "DEBUG:main function detects input file:""$FILEIN1" ;
+	vbm "DEBUG:contents of following file is displayed below:""$FILEIN1" ;
+	if [ "$OPTION_VERBOSE" == "true" ]; then # display FILEIN1 contents via cat if verbose mode specified
+	    echoerr "========""$FILEIN1"" START""========" ;
+	    cat "$FILEIN1" 1>&2 ;
+	    echoerr "========""$FILEIN1"" END""========" ;
+	fi
+    fi
+    
+    # Perform work
+    OUTPUT="$OUTPUT""Hello world.\n"
+    if [ -v FILEIN1 ]; then
+	OUTPUT="$OUTPUT""The b2sum hash of $FILEIN1 is: $(b2sum "$FILEIN1" | awk '{print $1}').\n";
+    fi
+    OUTPUT="$OUTPUT""The current time is:""$SCRIPT_TIME_SHORT\n"
+
+    # Output results
+    echo -e "$OUTPUT"
+
+    if [ -v FILEOUT1 ]; then  # if FILEOUT1 set, write to this file.
+	vbm "DEBUG:main function detects output file:""$FILEOUT1" ;
+	echo -e "$OUTPUT" > "$FILEOUT1" ;
+	vbm "DEBUG:main funtion wrote OUTPUT to:""$FILEOUT1" ;
+    elif [ -v DIROUT1 ]; then  # else if DIROUT1 set, set FILEOUT1 to timestamped filename, combine into PATHOUT1, write output to PATHOUT1.
+	vbm "DEBUG:main function detects output directory:""$DIROUT1" ;
+	FILEOUT1="$SCRIPT_TIME_SHORT"..output
+	PATHOUT1="$DIROUT1"/"$FILEOUT1"
+	echo -e "$OUTPUT" > $PATHOUT1 ;
+	vbm "DEBUG:main function wrote output file to:""$PATHOUT1" ;
+    fi
+
+    # End function
+    vbm "DEBUG:main function ended."
+    return 0; # Function finished.
+}
+
+#== Perform work and exit ==
+main "$@" # Run main function.
+exit 0;