BASH: dos2unix & unix2dos (Will work on OpenWRT devices as well)

dosunixconv.sh

#!/bin/sh
#
# This script will do the same as dos2unix and unix2dos, which are usable on Linux and Window.
# I made this so that i would be able to do the same on embedded devices like OpenWRT.
#
# Author: Andreas Nilsen <[email protected]> - @adde88 - http://www.github.com/adde88
# Date: 16. October 2024
#
#
function show_usage() {
    echo "Usage: $0 [dos2unix|unix2dos] <filename(s)>"
    echo "You can use wildcards for filename(s), e.g., *.txt"
    echo
    echo "Examples:"
    echo "  $0 dos2unix file.txt"
    echo "  $0 dos2unix *.cpp"
    echo "  $0 dos2unix *"
    echo "  $0 dos2unix file1.txt file2.txt file3.txt"
    echo -e "  Both dos2unix, and unix2dos can be used with the same arguments as demonstrated above.\n"
}

function dos2unix() {
    local file="$1"
    if [ ! -f "$file" ]; then
        echo "File not found: $file"
        return 1
    fi
    sed -i 's/\r$//' "$file"
    echo "Converted $file from DOS to UNIX format"
}

function unix2dos() {
    local file="$1"
    if [ ! -f "$file" ]; then
        echo "File not found: $file"
        return 1
    fi
    sed -i 's/$/\r/' "$file"
    echo "Converted $file from UNIX to DOS format"
}

# Check if no arguments or only one argument is provided
if [ $# -lt 2 ]; then
    echo "Error: Insufficient arguments provided."
    echo
    show_usage
    exit 1
fi

conversion_type="$1"
shift

case "$conversion_type" in
    dos2unix|unix2dos)
        files_processed=0
        for file in "$@"; do
            if [ -f "$file" ]; then
                $conversion_type "$file"
                ((files_processed++))
            else
                echo "Skipping $file: Not a regular file"
            fi
        done
        
        if [ $files_processed -eq 0 ]; then
            echo "Error: No valid files were processed."
            echo
            show_usage
            exit 1
        fi
        ;;
    *)
        echo "Error: Invalid conversion type. Use 'dos2unix' or 'unix2dos'."
        echo
        show_usage
        exit 1
        ;;
esac

I chose to use the shell for the work, as python seems to be quite slow on these devices compared to bash, or binaries compiled for the system, like C, C++