> Plus the -P flag is available on both GNU ...

    [pritam@PritePad ~]$ cat /etc/lsb-release 
    LSB_VERSION=1.4
    DISTRIB_ID=Arch
    DISTRIB_RELEASE=rolling
    DISTRIB_DESCRIPTION="Arch Linux"
    [pritam@PritePad ~]$ touch t
    [pritam@PritePad ~]$ rm -P t
    rm: invalid option -- 'P'
    Try 'rm --help' for more information.

`man rm` does suggest looking at shred(1) in the SEE ALSO section