parpass

#!/usr/bin/env bash
#
# parpass
#
# Version:    1.5.3
# History:    2020-06-14, 2020-07-11, 2023-11-15, 2023-11-19, 2023-11-20
#
# Project Description:
#
# Reads the password file /etc/passwd, searches for user names beginning with $1,
# and parses the record to print it in a human-readable form on the screen.
#
# Author:     Bernd Storck
# Contact:    https://www.facebook.com/BStLinux/
#
# Copyright:  2023, Bernd Storck
# License:    GNU General Public License 3.0

# Daten zur Selbstbeschreibung des Scripts: ...............
readonly ORIGINAL_SCRIPT_NAME="parpass"
readonly CURRENT_SCRIPT_NAME="${0##*/}"  ## Name of the script file
readonly TITLE="$ORIGINAL_SCRIPT_NAME (parsePasswd)"
readonly VERSION="1.5.3"
readonly VERSIONS_TIME_STAMP="2023-11-22 21:00:27"  # date +"%Y-%m-%d %T"


# Farbnamensvariablen: ....................................
readonly WHITE='\e[0;37m'
readonly WHITE_BOLD='\e[1;37m'
readonly YELLOW='\e[0;33m'
readonly YELLOW_BOLD='\e[1;33m'
readonly YELLOW_BOLD_INTENS='\e[1;93m'
readonly GREEN_BOLD='\e[1;32m'
readonly COLOROFF='\e[0m'

OLDIFS="$IFS"
IFS=":"

# Defines the name of the language file according to system language:
readonly language_file_name="parpass.lang.${LANG:0:2}"

# Searching for an external language file:
for config_path in "$HOME/parpass/" "$HOME/" "/etc/parpass/" "/etc/" "./"; do
  language_file="${config_path}$language_file_name"
  if [ -f "$language_file" ]; then
    source "${language_file}"
    file_found=true
    break
  fi
done

# If no language file is found the following
# will define English text as default output:
if ! "$file_found" ; then
  UILANG="English"
  label_ID="IDs (uid/gid)"
  label_homeDir="Directory"
  label_loginShell="Login Shell"
  label_realName="Real Name"
  label_room="Room"
  label_workPhone="Work Fon"
  label_phone="Home Phone"
  label_comment="Comment"
fi

# Functions: -----------------------------------------

usage () {
# Displays program purpose and usage help.

echo -e "${YELLOW_BOLD}$TITLE $VERSION ${COLOROFF}\n"

if [ "$UILANG" = "Deutsch" ]; then
  echo -e "Das Programm liest die Passwortdatei \"/etc/passwd\" und zeigt ihren Inhalt gut lesbar an.

AUFRUFPARAMETER:
  --help|-h|--hilf   # Diese Hilfe anzeigen
  --version|-V       # Die Version dieses Installationsskripts anzeigen.
  --full_version     # Eine ausführliche Versionsinformation anzeigen.

BEISPIELAUFRUFE:
  ${GREEN_BOLD}Aufruf            Beschreibung${COLOROFF}

  $CURRENT_SCRIPT_NAME root   # Zeigt die Daten aus der passwd zum Account root an.
  $CURRENT_SCRIPT_NAME bs     # Zeigt die Daten zu allen Accounts an, die mit \"bs\" beginnen.
  $CURRENT_SCRIPT_NAME        # Zeigt die Daten aus der Datei passwd zu allen Accounts an.
"
else  # English help:
  echo -e "Reads the password file \"/etc/passwd\" and displays its content human-readable on the screen.

PARAMETERS:
  --help|-h|--hilf   # Display this help.
  --version|-V       # Display the script version.
  --full_version     # Display detailed version information.

EXAMPLES:
  ${GREEN_BOLD}Call              Description${COLOROFF}

  $CURRENT_SCRIPT_NAME root   # Shows information from passwd according to the account. \"root\".
  $CURRENT_SCRIPT_NAME bs     # Shows information about all accounts, which do begin with \"bs\".
  $CURRENT_SCRIPT_NAME        # Shows information from file \"passwd\" for all accounts.\n"
fi
}


print_program_identification () {
# Gibt die vollstaendige Programmselbstbezeichnung aus.
  printf "\n${WHITE}%s (%s, %s, %s)${COLOROFF}\n\n" \
  "$PROG_NAME" "$ORIGINAL_SCRIPT_NAME" "$VERSION" "$VERSIONS_TIME_STAMP"
}


normalize_option () {
# Wenn eine Option mehr als einen Buchstaben hat, korrigiert diese Funktion
# beispielsweise '-examples' zu '--examples'.
#
# Zudem wandelt sie mehrbuchstabige Optionen in Kleinbuchstaben um.
#
  local input="$1"
  local output="$input"

  if [[ ! "$1" =~ ^[a-zA-Z0-9] ]]; then
    input="$input"
    # Prueft mit bash-internen Kommandos, ob die Option mit nur genau einem '-'
    # beginnt und darauf mindestens zwei Buchtaben folgen und ersetzt
    # gegebenenfalls das '-' am Anfang durch '--':
    if [[ $input =~ ^-([a-zA-Z]{2,}) ]]; then
      output="--${BASH_REMATCH[1]}"
      output="${output,,}"  # Converts to lower case.
    fi
  fi
  echo "$output"
}


internal_filter () {
# Replaces functionallity of the programs 'look', 'grep' etc.,
# if none of those is available.
  local lines
  while read -r line; do
    if [[ "$line" =~ ^$1 ]]; then
      lines+="$line\n"
    fi
  done < /etc/passwd
  printf "%b" "$lines"
}


getLines () {
# Filters those lines which are beginning with "$1".
#
  local line_start="$1"
  local data_file
  local prog
  local program_found
  local answer

  [ ! "$2" ] && data_file="/etc/passwd" || data_file="$2"

  for prog in look rg grep agrep tre-agrep; do
    if command -v "$prog" > /dev/null 2>&1; then
      case "$prog" in
        look)
          answer="$(look "$line_start" "$data_file")"
          ;;
        rg)
          answer="$(rg -N "^$line_start" "$data_file")"
          ;;
        grep|agrep|tre-agrep)
          answer="$($prog "^$line_start" "$data_file")"
          ;;
      esac
      program_found=true
      break
    fi
  done

  if ! "$program_found"; then
    answer="$(internal_filter "$1")"
  fi

  echo "$answer"
}


plotHeadLine () {
  local len
  local line=

  len="$(( 62 - ${#1} ))"

  echo -en "\n${YELLOW_BOLD_INTENS}${user} ${YELLOW}"
  for ((i=0; i<len; i++ )); do
    line+="-"
  done
  echo -e "$line${COLOROFF}";
}


printField() {
# Pairs of field names and their content are written to a variable,
# allowing the result to be reformatted at the end once all fields
# of a data set are collected in the variable.
  dataSet+="\t${WHITE_BOLD}${2}:${COLOROFF}# ${1}\n"
}


printNotEmpty() {
  if [ "$1" != "" ]; then
    printField "$1" "$2"
  fi
}


internal_column () {
# Replaces the external program 'column', if it is not available.
  local line
  local maxLen=0

  while read -r line; do
    field1="${line%%#*}"  # Like: field1="$(cut -d'#' -f1 <<< "$line")"
    if [ "${#field1}" -gt "$maxLen" ]; then
      maxLen="${#field1}"
    fi
  done <<< "$1"

  while read -r line; do
    IFS="#" read -r field1 field2 <<< "${line}"
    printf "%-${maxLen}b %b\n" "$field1" "$field2"
  done <<< "$1"
}


external_output () {
  echo -e "$1" | column -s# -t
}


internal_output () {
  internal_column "$(echo -e "$1")"
}




# Main: ----------------------------------------------

option=$(normalize_option "$1")
case "$option" in
  --help|-h|--hilf|-help)
    usage
    exit 0
    ;;
  --version|-V)
    printf "%s (Version %s)\n" "$ORIGINAL_SCRIPT_NAME" "$VERSION"
    exit 0
    ;;
  --fullversion|--id|--identifi[ck]ation)
    print_program_identification
    exit 0
    ;;
  -\#)  # Versionsnummer anzeigen
    echo "$VERSION"
    exit 0
    ;;
  *)
    unset option
    ;;
esac


if command -v column > /dev/null 2>&1; then
  printData="external_output"
else
  printData="internal_output"
fi

lines="$(getLines "$1")"
if [ -n "$lines" ]; then
  while read -r user trash uid gid data homeDir loginShell; do
    plotHeadLine "$user"
    printField "$uid / $gid" "$label_ID"
    printField "$homeDir" "$label_homeDir"
    printField "$loginShell" "$label_loginShell"

    IFS=','
    read -r realName room workPhone phone comment <<< "$data"

    printNotEmpty "$realName" "$label_realName"
    printNotEmpty "$room" "$label_room"
    printNotEmpty "$workPhone" "$label_workPhone"
    printNotEmpty "$phone" "$label_phone"
    printNotEmpty "$comment" "$label_comment"

    "$printData" "$dataSet"  # Prints data set to screen.

    unset dataSet
    IFS=':'
  done <<< "$lines"
fi

IFS="$OLDIFS"

exit 0