NAME
rm —
remove directory entries
SYNOPSIS
rm |
[-f | -i]
[-dPRrvWx] file ... |
DESCRIPTION
Therm utility attempts to remove the non-directory type
files specified on the command line. If the permissions of the file do not
permit writing, and the standard input device is a terminal, the user is
prompted (on the standard error output) for confirmation.
The options are as follows:
-d- Attempt to remove directories as well as other types of files.
-f- Attempt to remove the files without prompting for confirmation, regardless
of the file's permissions. If the file does not exist, do not display a
diagnostic message or modify the exit status to reflect an error. The
-foption overrides any previous-ioptions. -i- Request confirmation before attempting to remove each file, regardless of
the file's permissions, or whether or not the standard input device is a
terminal. The
-ioption overrides any previous-foptions. -P- Overwrite regular files before deleting them. Files are overwritten three times, first with the byte pattern 0xff, then 0x00, and then with random data, before they are deleted. Some care is taken to ensure that the data are actually written to disk, but this cannot be guaranteed, even on traditional filesystems; on log-structured filesystems or if any block-journaling scheme is in use, this option is completely useless. If the file cannot be overwritten, it will not be removed.
-R- Attempt to remove the file hierarchy rooted in each file argument. The
-Roption implies the-doption. If the-ioption is specified, the user is prompted for confirmation before each directory's contents are processed (as well as before the attempt is made to remove the directory). If the user does not respond affirmatively, the file hierarchy rooted in that directory is skipped. -r- Equivalent to
-R. -v- Cause
rmto be verbose, showing files as they are processed. -W- Attempts to undelete the named files. Currently, this option can only be used to recover files covered by whiteouts.
-x- When removing a hierarchy, do not cross mount points.
The rm utility removes symbolic links, not
the files referenced by the links.
It is an error to attempt to remove the files ``.'' and ``..''.
EXIT STATUS
The rm utility exits 0 if all of the named
files or file hierarchies were removed, or if the -f
option was specified and all of the existing files or file hierarchies were
removed. If an error occurs, rm exits with a value
>0.
EXAMPLES
rm uses
getopt(3) standard argument processing. Removing filenames that begin
with a dash (e.g., -file) in the current directory
which might otherwise be taken as option flags to rm
can be accomplished as follows:
rm -- -file
or
rm ./-file
COMPATIBILITY
The rm utility differs from historical
implementations in that the -f option only masks
attempts to remove non-existent files instead of masking a large variety of
errors.
Also, historical BSD implementations prompted on the standard output, not the standard error output.
SEE ALSO
rmdir(1), undelete(2), unlink(2), fts(3), getopt(3), symlink(7)
STANDARDS
The rm utility is expected to be
IEEE Std 1003.2 (“POSIX.2”)
compatible. The -v and -x
options are extensions.
The -P option attempts to
conform to U.S. DoD 5220-22.M, "National Industrial Security Program
Operating Manual" ("NISPOM") as updated by Change 2 and the
July 23, 2003 "Clearing & Sanitization Matrix". However,
unlike earlier revisions of NISPOM, the 2003 matrix imposes requirements
which make it clear that the standard does not and can not apply to the
erasure of individual files, in particular requirements relating to spare
sector management for an entire magnetic disk.
Because these
requirements are not met, the -P
option does
not conform to the standard.
HISTORY
An rm utility appeared in
Version 1 AT&T UNIX.
BUGS
The -P option assumes that the underlying
file system is a fixed-block file system. FFS is a fixed-block file system,
LFS is not. In addition, only regular files are overwritten, other types of
files are not. Recent research indicates that as many as 35 overwrite passes
with carefully chosen data patterns may be necessary to actually prevent
recovery of data from a magnetic disk. Thus the -P
option is likely both insufficient for its design purpose and far too costly
for default operation. However, it will at least prevent the recovery of
data from FFS volumes with
fsdb(8).