The rm utility shall remove the directory entry specified by each file argument.
If either of the files dot or dot-dot are specified as the basename portion of an operand (that is, the final pathname component), rm shall write a diagnostic message to standard error and do nothing more with such operands.
For each file the following steps shall be taken:
If this fails for any reason, rm shall write a diagnostic message to standard error, do nothing more with the current file, and go on to any remaining files.
The rm utility shall be able to descend to arbitrary depths in a file hierarchy, and shall not fail due to path length limitations (unless an operand specified by the user exceeds system limitations).
The rm utility shall conform to the Base Definitions volume of IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
The following options shall be supported:
The following operand shall be supported:
The standard input shall be used to read an input line in response to each prompt specified in the STDOUT section. Otherwise, the standard input shall not be used.
The following environment variables shall affect the execution of rm:
Determine the locale for the behavior of ranges, equivalence classes, and multi-character collating elements used in the extended regular expression defined for the yesexpr locale keyword in the LC_MESSAGES category.
Prompts shall be written to standard error under the conditions specified in the DESCRIPTION and OPTIONS sections. The prompts shall contain the file pathname, but their format is otherwise unspecified. The standard error also shall be used for diagnostic messages.
The following exit values shall be returned:
Default.
The following sections are informative.
The rm utility is forbidden to remove the names dot and dot-dot in order to avoid the consequences of inadvertently doing something like:
rm -r .*
Some implementations do not permit the removal of the last link to an executable binary file that is being executed; see the [EBUSY] error in the unlink() function defined in the System Interfaces volume of IEEE Std 1003.1-2001. Thus, the rm utility can fail to remove such files.
The -i option causes rm to prompt and read the standard input even if the standard input is not a terminal, but in the absence of -i the mode prompting is not done when the standard input is not a terminal.
rm a.out core
removes the directory entries: a.out and core.
rm -Rf junk
removes the directory junk and all its contents, without prompting.
For absolute clarity, paragraphs (2b) and (3) in the DESCRIPTION of rm describing the behavior when prompting for confirmation, should be interpreted in the following manner:
if ((NOT f_option) AND
((not_writable AND input_is_terminal) OR i_option))
The exact format of the interactive prompts is unspecified. Only the general nature of the contents of prompts are specified because implementations may desire more descriptive prompts than those used on historical implementations. Therefore, an application not using the -f option, or using the -i option, relies on the system to provide the most suitable dialog directly with the user, based on the behavior specified.
The -r option is historical practice on all known systems. The synonym -R option is provided for consistency with the other utilities in this volume of IEEE Std 1003.1-2001 that provide options requesting recursive descent through the file hierarchy.
The behavior of the -f option in historical versions of rm is inconsistent. In general, along with "forcing" the unlink without prompting for permission, it always causes diagnostic messages to be suppressed and the exit status to be unmodified for nonexistent operands and files that cannot be unlinked. In some versions, however, the -f option suppresses usage messages and system errors as well. Suppressing such messages is not a service to either shell scripts or users.
It is less clear that error messages regarding files that cannot be unlinked (removed) should be suppressed. Although this is historical practice, this volume of IEEE Std 1003.1-2001 does not permit the -f option to suppress such messages.
When given the -r and -i options, historical versions of rm prompt the user twice for each directory, once before removing its contents and once before actually attempting to delete the directory entry that names it. This allows the user to "prune" the file hierarchy walk. Historical versions of rm were inconsistent in that some did not do the former prompt for directories named on the command line and others had obscure prompting behavior when the -i option was specified and the permissions of the file did not permit writing. The POSIX Shell and Utilities rm differs little from historic practice, but does require that prompts be consistent. Historical versions of rm were also inconsistent in that prompts were done to both standard output and standard error. This volume of IEEE Std 1003.1-2001 requires that prompts be done to standard error, for consistency with cp and mv, and to allow historical extensions to rm that provide an option to list deleted files on standard output.
The rm utility is required to descend to arbitrary depths so that any file hierarchy may be deleted. This means, for example, that the rm utility cannot run out of file descriptors during its descent (that is, if the number of file descriptors is limited, rm cannot be implemented in the historical fashion where one file descriptor is used per directory level). Also, rm is not permitted to fail because of path length restrictions, unless an operand specified by the user is longer than {PATH_MAX}.
The rm utility removes symbolic links themselves, not the files they refer to, as a consequence of the dependence on the unlink() functionality, per the DESCRIPTION. When removing hierarchies with -r or -R, the prohibition on following symbolic links has to be made explicit.
rmdir() , the System Interfaces volume of IEEE Std 1003.1-2001, remove(), rmdir(), unlink()