bash - input checker, if arg is a file

1_CheckFileInput.sh

#!/bin/bash
if [ $# != 1 ]; then
    echo -ne "\e[31m[-] Input only 1 arg\e[00m\n"
else
    echo -ne "\e[32m[+] 1 arg ok\e[00m\n"
    if [ -f "$1" ]; then
        echo -ne "\e[32m[+] arg 1 IS A file.\e[00m\n"
        f="$1"
        
        #echo "[*] exec: ls  $f"
        #ls --size --human-readable --inode --color=yes -1 "$f"
        
        #echo "[*] exec: checksum  $f"
        #sha1sum "$f"
        
    else
        echo -ne "\e[31m[-]arg 1 IS NOT:  a file OR found.\e[00m\n"
    fi
fi