Simple awk script to convert permissions to octal ( good for learning octal permissions )

lso.sh

#!/bin/sh

ls -l | awk '{
    k = 0
    s = 0
    for( i = 0; i <= 8; i++ )
    {
        k += ( ( substr( $1, i+2, 1 ) ~ /[rwxst]/ ) * 2 ^( 8 - i ) )
    }
    j = 4
    for( i = 4; i <= 10; i += 3 )
    {
        s += ( ( substr( $1, i, 1 ) ~ /[stST]/ ) * j )
        j/=2
    }
    if ( k )
    {
        printf( "%0o%0o ", s, k )
    }
    print
}'