truncate -- truncate or extend the length of files
truncate [-c] -s [+|-]size[K|M|G] file ...
truncate [-c] -r rfile file ...
The truncate utility adjusts the length of each regular file given on the
command-line.
The following options are available:
-c Do not create files if they do not exist. The truncate utility
does not treat this as an error. No error messages are displayed
and the exit value is not affected.
-r rfile
Truncate files to the length of the file rfile.
-s [+|-]size[K|M|G]
If the size argument is preceded by a plus sign (+), files will
be extended by this number of bytes. If the size argument is
preceded by a dash (-), file lengths will be reduced by no more
than this number of bytes, to a minimum length of zero bytes.
Otherwise, the size argument specifies an absolute length to
which all files should be extended or reduced as appropriate.
The size argument may be suffixed with one of K, M or G to indicate
a multiple of Kilobytes, Megabytes or Gigabytes respectively.
Exactly one of the -r and -s options must be specified.
If a file is made smaller, its extra data is lost. If a file is made
larger, it will be extended as if by writing bytes with the value zero.
If the file does not exist, it is created unless the -c option is specified.
Note that, while truncating a file causes space on disk to be freed,
extending a file does not cause space to be allocated. To extend a file
and actually allocate the space, it is necessary to explicitly write data
to it, using (for example) the shell's `>>' redirection syntax, or dd(1).
The truncate utility exits 0 on success, and >0 if an error occurs. If
the operation fails for an argument, truncate will issue a diagnostic and
continue processing the remaining arguments.
dd(1), touch(1), truncate(2)
The truncate utility conforms to no known standards.
The truncate utility first appeared in FreeBSD 4.2.
The truncate utility was written by Sheldon Hearn
<sheldonh@starjuice.net>.
FreeBSD 5.2.1 July 4, 2000 FreeBSD 5.2.1 [ Back ] | 