+appendFileTar(){
+    # Desc: Processes first file and then appends to tar
+    # Usage: appendFileTar [file path] [name of file to be inserted] [tar path] [temp dir] ([cmd1] [cmd2] [cmd3] [cmd4]...)
+    # Version: 1.0.2
+    # Input: arg1: path of file to be (processed and) written
+    #        arg2: name to use for file inserted into tar
+    #        arg3: tar archive path (must exist first)
+    #        arg4: temporary working dir
+    #        arg5+: command strings (ex: "gpsbabel -i nmea -f - -o kml -F - ")
+    # Output: file written to disk
+    # Example: decrypt multiple large files in parallel
+    #          appendFileTar /tmp/largefile1.gpg "largefile1" $HOME/archive.tar /tmp "gpg --decrypt" &
+    #          appendFileTar /tmp/largefile2.gpg "largefile2" $HOME/archive.tar /tmp "gpg --decrypt" &
+    #          appendFileTar /tmp/largefile3.gpg "largefile3" $HOME/archive.tar /tmp "gpg --decrypt" &
+    # Depends: bash 5
+
+    # Save function name
+    local FN="${FUNCNAME[0]}";
+    #yell "DEBUG:STATUS:$FN:Finished appendFileTar()."
+    
+    # Set file name
+    if ! [ -z "$2" ]; then FILENAME="$2"; else yell "ERROR:$FN:Not enough arguments."; exit 1; fi
+    # Check tar path is a file
+    if [ -f "$3" ]; then TAR_PATH="$3"; else yell "ERROR:$FN:Tar archive arg not a file."; exit 1; fi
+    # Check temp dir arg
+    if ! [ -z "$4" ]; then TMP_DIR="$4"; else yell "ERROR:$FN:No temporary working dir set."; exit 1; fi
+    # Set command strings
+    if ! [ -z "$5" ]; then CMD1="$5"; else CMD1="tee /dev/null "; fi # command string 1
+    if ! [ -z "$6" ]; then CMD2="$6"; else CMD2="tee /dev/null "; fi # command string 2
+    if ! [ -z "$7" ]; then CMD3="$7"; else CMD3="tee /dev/null "; fi # command string 3
+    if ! [ -z "$8" ]; then CMD4="$8"; else CMD4="tee /dev/null "; fi # command string 4
+
+    # Input command string
+    CMD0="cat \"\$1\""
+    
+    # # Debug
+    # yell "DEBUG:STATUS:$FN:CMD0:$CMD0"
+    # yell "DEBUG:STATUS:$FN:CMD1:$CMD1"
+    # yell "DEBUG:STATUS:$FN:CMD2:$CMD2"
+    # yell "DEBUG:STATUS:$FN:CMD3:$CMD3"
+    # yell "DEBUG:STATUS:$FN:CMD4:$CMD4"
+    # yell "DEBUG:STATUS:$FN:FILENAME:$FILENAME"
+    # yell "DEBUG:STATUS:$FN:TAR_PATH:$TAR_PATH"
+    # yell "DEBUG:STATUS:$FN:TMP_DIR:$TMP_DIR"
+    
+    # Write to temporary working dir
+    eval "$CMD0 | $CMD1 | $CMD2 | $CMD3 | $CMD4" > "$TMP_DIR"/"$FILENAME";
+
+    # Append to tar
+    try tar --append --directory="$TMP_DIR" --file="$TAR_PATH" "$FILENAME";
+    #yell "DEBUG:STATUS:$FN:Finished appendFileTar()."
+} # Append file to Tar archive
+checkAgePubkey() {
+    # Desc: Checks if string is an age-compatible pubkey
+    # Usage: checkAgePubkey [str pubkey]
+    # Version: 0.1.2
+    # Input: arg1: string
+    # Output: return code 0: string is age-compatible pubkey
+    #         return code 1: string is NOT an age-compatible pubkey
+    #         age stderr (ex: there is stderr if invalid string provided)
+    # Depends: age (v0.1.0-beta2; https://github.com/FiloSottile/age/releases/tag/v1.0.0-beta2 )
+    
+    argPubkey="$1";
+    
+    if echo "test" | age -a -r "$argPubkey" 1>/dev/null; then
+       return 0;
+    else
+       return 1;
+    fi;
+} # Check age pubkey
+validateInput() {
+    # Desc: Validates Input
+    # Usage: validateInput [str input] [str input type]
+    # Version: 0.3.0
+    # Input: arg1: string to validate
+    #        arg2: string specifying input type (ex:"ssh_pubkey")
+    # Output: return code 0: if input string matched specified string type
+    # Depends: bash 5, yell
+
+    # Save function name
+    local FN="${FUNCNAME[0]}";
+
+    # Process arguments
+    argInput="$1";
+    argType="$2";
+    if [[ $# -gt 2 ]]; then yell "ERROR:$0:$FN:Too many arguments."; exit 1; fi;
+
+    # Check for blank
+    if [[ -z "$argInput" ]]; then return 1; fi
+    
+    # Define input types
+    ## ssh_pubkey
+    ### Check for alnum/dash base64 (ex: "ssh-rsa AAAAB3NzaC1yc2EAAA")
+    if [[ "$argType" = "ssh_pubkey" ]]; then
+       if [[ "$argInput" =~ ^[[:alnum:]-]*[\ ]*[[:alnum:]+/=]*$ ]]; then
+           return 0; fi; fi;
+
+    ## age_pubkey
+    ### Check for age1[:bech32:]
+    if [[ "$argType" = "age_pubkey" ]]; then
+       if [[ "$argInput" =~ ^age1[qpzry9x8gf2tvdw0s3jn54khce6mua7l]*$ ]]; then
+           return 0; fi; fi
+
+    ## integer
+    if [[ "$argType" = "integer" ]]; then
+       if [[ "$argInput" =~ ^[[:digit:]]*$ ]]; then
+           return 0; fi; fi;
+
+    ## time element (year, month, week, day, hour, minute, second)
+    if [[ "$argType" = "time_element" ]]; then
+       if [[ "$argInput" = "year" ]] || \
+              [[ "$argInput" = "month" ]] || \
+              [[ "$argInput" = "week" ]] || \
+              [[ "$argInput" = "day" ]] || \
+              [[ "$argInput" = "hour" ]] || \
+              [[ "$argInput" = "minute" ]] || \
+              [[ "$argInput" = "second" ]]; then
+           return 0; fi; fi;
+    
+    # Return error if no condition matched.
+    return 1;
+} # Validates strings