i have liked the Debian "srm" for years
it builds on Fedora on rhel and is in the Opensuse base packages
Usage: srm [OPTION]... [FILE]...
Overwrite and remove (unlink) the files.
-d, --directory ignored (for compatability with rm(1))
-f, --force ignore nonexistant files, never prompt
-i, --interactive prompt before any removal
-x, --one-file-system do not cross file system boundaries
-s, --simple overwrite with single pass using 0x00
-P, --openbsd overwrite with three passes like OpenBSD rm
-D, --dod overwrite with 7 US DoD compliant passes
-E, --doe overwrite with 3 US DoE compliant passes
-r, -R, --recursive remove the contents of directories
-v, --verbose explain what is being done
-h, --help display this help and exit
-V, --version display version information and exit
BUT!!! and it is a VERY BIG BUTT
modern file systems might not write the data to the exact same sector
however there is a work around " dd"
you use it to make one honking HUGE file in the partition using rand or zero
for the root " / " partition
dd if=/dev/zero of=/BIG_FILE.bin
and use the mount point for other partitions