Visit Our UNIX and Linux User Community

Linux and UNIX Man Pages

Test Your Knowledge in Computers #259
Difficulty: Easy
Steve Jobs was born in San Francisco, California, and put up for adoption.
True or False?
Linux & Unix Commands - Search Man Pages

truncate(2) [bsd man page]

TRUNCATE(2)							System Calls Manual						       TRUNCATE(2)

NAME
truncate - truncate a file to a specified length SYNOPSIS
truncate(path, length) char *path; off_t length; ftruncate(fd, length) int fd; off_t length; DESCRIPTION
Truncate causes the file named by path or referenced by fd to be truncated to at most length bytes in size. If the file previously was larger than this size, the extra data is lost. With ftruncate, the file must be open for writing. RETURN VALUES
A value of 0 is returned if the call succeeds. If the call fails a -1 is returned, and the global variable errno specifies the error. ERRORS
Truncate succeeds unless: [ENOTDIR] A component of the path prefix is not a directory. [EINVAL] The pathname contains a character with the high-order bit set. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [ENOENT] The named file does not exist. [EACCES] Search permission is denied for a component of the path prefix. [EACCES] The named file is not writable by the user. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EISDIR] The named file is a directory. [EROFS] The named file resides on a read-only file system. [ETXTBSY] The file is a pure procedure (shared text) file that is being executed. [EIO] An I/O error occurred updating the inode. [EFAULT] Path points outside the process's allocated address space. Ftruncate succeeds unless: [EBADF] The fd is not a valid descriptor. [EINVAL] The fd references a socket, not a file. [EINVAL] The fd is not open for writing. SEE ALSO
open(2) BUGS
These calls should be generalized to allow ranges of bytes in a file to be discarded. 4.2 Berkeley Distribution March 29, 1986 TRUNCATE(2)

Check Out this Related Man Page

TRUNCATE(2)						      BSD System Calls Manual						       TRUNCATE(2)

NAME
truncate, ftruncate -- truncate or extend a file to a specified length LIBRARY
Standard C Library (libc, -lc) SYNOPSIS
#include <unistd.h> int truncate(const char *path, off_t length); int ftruncate(int fd, off_t length); DESCRIPTION
The truncate() system call causes the file named by path or referenced by fd to be truncated or extended to length bytes in size. If the file was larger than this size, the extra data is lost. If the file was smaller than this size, it will be extended as if by writing bytes with the value zero. With ftruncate(), the file must be open for writing. RETURN VALUES
Upon successful completion, the value 0 is returned; otherwise the value -1 is returned and the global variable errno is set to indicate the error. If the file to be modified is not a directory or a regular file, the truncate() call has no effect and returns the value 0. ERRORS
The truncate() system call succeeds unless: [ENOTDIR] A component of the path prefix is not a directory. [ENAMETOOLONG] A component of a pathname exceeded 255 characters, or an entire path name exceeded 1023 characters. [ENOENT] The named file does not exist. [EACCES] Search permission is denied for a component of the path prefix. [EACCES] The named file is not writable by the user. [ELOOP] Too many symbolic links were encountered in translating the pathname. [EPERM] The named file has its immutable or append-only flag set, see the chflags(2) manual page for more information. [EISDIR] The named file is a directory. [EROFS] The named file resides on a read-only file system. [ETXTBSY] The file is a pure procedure (shared text) file that is being executed. [EFBIG] The length argument was greater than the maximum file size. [EINVAL] The length argument was less than 0. [EIO] An I/O error occurred updating the inode. [EFAULT] The path argument points outside the process's allocated address space. The ftruncate() system call succeeds unless: [EBADF] The fd argument is not a valid descriptor. [EINVAL] The fd argument references a socket, not a file. [EINVAL] The fd descriptor is not open for writing. SEE ALSO
chflags(2), open(2) HISTORY
The truncate() system call appeared in 4.2BSD. BUGS
These calls should be generalized to allow ranges of bytes in a file to be discarded. Use of truncate() to extend a file is not portable. BSD
December 13, 2006 BSD

Featured Tech Videos