Check permissions in Unix while executing a script

$ cat check-permissions.sh

#!/bin/bash

file=$1

# Handle non-absolute paths

if ! [[ "$file" == /* ]] ; then

    path=.

fi

dirname "$file" | tr '/' $'\n' | while read part ; do

    path="$path/$part"

    # Check for execute permissions

    if ! [[ -x "$path" ]] ; then

        echo "'$path' is blocking access."

    fi

done

if ! [[ -r "$file" ]] ; then

    echo "'$file' is not readable."

fi

$ ./check-permissions.sh /long/path/to/file.txt