#!/bin/bash

list_users() {
    awk -F: '{print $1, $6}' /etc/passwd | sort
}

list_processes() {
    ps -eo pid,comm --sort=pid
}

show_help() {
    echo "Usage: $0 [options]."
    echo "Options:"
    echo "  -u, --users       Display a list of users and their home directories"
    echo "  -p, --processes   Display a list of running processes"
    echo "  -l, --log PATH    Redirect output to a specified file"
    echo "  -e, --errors PATH Redirect error output to a specified file"
    echo "  -h, --help        Show this message and terminate"
}

check_path() {
    local path=$1
    if [ ! -w "$path" ]; then
        echo "Error: No access to write to $path" >&2
        exit 1
    fi
}

log_output() {
    local path=$1
    check_path "$path"
    exec >"$path"
}

log_errors() {
    local path=$1
    check_path "$path"
    exec 2>"$path"
}

ARGS=$(getopt -o upl:e:h --long users,processes,log:,errors:,help -n "$0" -- "$@")
if [ $? -ne 0 ]; then
    echo "Error: Incorrect input" >&2
    exit 1
fi
eval set -- "$ARGS"

while true; do
    case "$1" in
        -u|--users)
            list_users
            shift
            ;;
        -p|--processes)
            list_processes
            shift
            ;;
        -l|--log)
            log_output "$2"
            shift 2
            ;;
        -e|--errors)
            log_errors "$2"
            shift 2
            ;;
        -h|--help)
            show_help
            exit 0
            ;;
        --)
            shift
            break
            ;;
        *)
            echo "Unknown parameter $1" >&2
            exit 1
            ;;
    esac
done