Util to copy file/dir from one user to another. This includes parsing relative paths to a user's home, updating ownership, and modifying file contents to home path changes (e.g. /home/foo -> /home/bar).

cp-from-user.sh

#!/bin/env bash
set -e
set -o pipefail  

display_help() {                                                          
    echo "Usage: cp-from-user [option...] --path <PATH> --source-user <SRC-USER> [--destination-user <DST-USER>]"                                               
    echo                                                                  
    echo "Util to copy file or directory from one user to another"
    echo                                                                 
    echo "  -p, --path <PATH>                  Path to the file or directory from home directory."
    echo "                                     Accepts both relative path and a relative path to"
    echo "                                     the src user's home directory"
    echo "  -s, --source-user <SRC-USER>       Source user from which to copy the file or directory"
    echo "  -d, --destination-user <DST-USER>  Destination user to which to copy the file or"
    echo "                                     directory. Defaults to current user"
    echo "  -h, --help                         Display help messages"

    exit 0
}

cp_from_user() {
    local path_rel_to_home
    local src_user
    local dst_user

    while [ "$#" -gt 0 ]; do
        case "$1" in
        -p | --path)
            path_rel_to_home="$2"
            shift 2
            ;;
        -s | --source-user)
            src_user="$2"
            shift 2
            ;;
        -d | --destination-user)
            dst_user="$2"
            shift 2
            ;;
        -h | --help)
            display_help
            ;;
        --) # end argument parsing
            shift
            break
            ;;
        -*)
            echo "Error: Unsupported flag $1" >&2
            exit 1
            ;;
        *) # preserve positional arguments
            PARAMS="$PARAMS $1"
            shift
            ;;
        esac
    done
    # set positional arguments in their proper place
    eval set -- "$PARAMS"

    if [ -z "$path_rel_to_home" ]; then
        echo "Error: path must be provided"
        exit 1
    fi
    if [ -z "$src_user" ]; then
        # check if path_rel_to_home is provided contains /root or /home/<user>
        # if /root, set src_user to root
        if [ "${path_rel_to_home:0:5}" == "/root" ]; then 
            src_user="root"
        # if /home/<user>, set src_user to <user>
        elif [[ "${path_rel_to_home:0:6}" == "/home/"* ]]; then
            src_user="${path_rel_to_home:6}"
            src_user="${src_user%%/*}"
        else
            echo "Error: source user must be provided"
            exit 1
        fi
    fi
    
    # set default value for dst_user if not provided
    [ -z "$dst_user" ] && dst_user="$(whoami)"

    local src_home
    local src
    # dst
    local dst_home
    local dst

    # check if root or not root for $2. If not root, set src_home to /home/$2 else set src_home to /root
    if [ "$src_user" != "root" ]; then
        src_home="/home/$src_user"
        if [ ! -d "$src_home" ]; then
            echo "Error: $src_home does not exist"
            exit 1
        fi
    else
        src_home="/root"
    fi


    if [ "$dst_user" != "root" ]; then
        dst_home="/home/$dst_user"
        if [ ! -d "$dst_home" ]; then
            echo "Error: $dst_user does not exist"
            exit 1
        fi
    else
        dst_home="/root"
    fi

    if [[ "$src_user" == "$dst_user" ]]; then
        echo "source and current users are the same."
        exit 1
    fi

    # remove src_home from path_rel_to_home
    path_rel_to_home="${path_rel_to_home#"${src_home}"/}"

    src="$src_home/$path_rel_to_home"
    dst="$dst_home/$path_rel_to_home"

    # remove // from both src and dst (possible artifact from joining vars)
    src="${src//\/\//\/}"
    dst="${dst//\/\//\/}"

    # remove dst if exits, but with user confirmation
    if [ -e "$dst" ]; then
        read -p "Do you want to remove $dst? [y/N] " -n 1 -r
        echo
        if [[ $REPLY =~ ^[Yy]$ ]]; then
            rm -rf "$dst"
        else
            echo "Aborted"
            exit 1
        fi
    fi

    echo -e '\n-------------------------------------------------'
    echo "SOURCE USER: $src_user"
    echo "SOURCE FILE: '$src'"
    echo "DEST. USER: $dst_user"
    echo "DEST. FILE: '$dst'"
    echo -e '-------------------------------------------------\n'

    # check if src exist (either file or directory)
    if [ ! -e "$src" ]; then
        echo "Error: $src does not exist"
        exit 1
    fi

    mkdir -p "$(dirname "$dst")" >/dev/null 2>&1

    if [ -d "$src" ]; then
        # if src is a directory, copy recursively
        cp -rvf "$src" "$dst"
    
        # change group and/or user ownership inline with original file
        chown -R "$(stat -c "%U:%G" "$src")//$src_user/$dst_user" "$dst"

        # iterate through files and ensure all old $HOME paths are replaced with the current user
        for i in $(find "$dst" -type f); do
            sed i "s|$src_home|$dst_home|g" "$i" > /dev/null 2>&1
        done

    else
        # if src is a file, copy
        cp -vf "$src" "$dst"
        
        # fix ownership
        chown "$(stat -c "%U:%G" "$src")//${src_user}/${dst_user}" "$dst"
        
        # fix home path
        sed i "s|$src_home|$dst_home|g" "$dst" > /dev/null 2>&1
    fi

    exit 0
}

### main ###
# help if no args or -h or --help is passed
if [[ $# -eq 0 ]] || [[ "$*" == *"-h"* ]] || [[ "$*" == *"--help"* ]]; then
    display_help
fi

cp_from_user "$@"