NAME¶
since - display content of a file since the last time
SYNOPSIS¶
since [-aefhlmnqvxz] [-d seconds] [-s
file] files
DESCRIPTION¶
since is a utility designed to monitor log files.
since is similar
to
tail(2) as it also displays information appended to a file. However
since only displays the data which has been added
since the last
time
since was run. If
since is run on a particular file for the
first time, then the entire file is displayed.
EXAMPLE¶
since /var/log/apache/{access,error}_log > /dev/null
lynx --dump http://localhost/ > /dev/null
since /var/log/apache/{access,error}_log
OPTIONS¶
- -a
- Make updates to the since state files atomic. This option
configures since to use a temporary file and a rename(2)
instead of updating the state file in situ.
- -d seconds
- Specify the number of integer seconds to wait between
polling files for changes. This option is only relevant in conjunction
with the -f option and if the inotify mechanism is not being used.
- -e
- Print the header lines to standard error instead of
standard output.
- -f
- Follow the specified files. This option is analogous to
tail -f as the files are also polled for changes until the process
is interrupted.
- -h
- Print a terse help message.
- -l
- Relaxed mode. If some data files are inaccessible
since will not fail completely.
- -m
- Disable mmap(2), use read(2) instead to
access state and data files. Note that for certain smaller io operations
read(2) may be used even if this option has not been given.
- -n
- Do not update the .since file which keeps track of
file growth.
- -q
- Make the utility operate more quietly.
- -s filename
- Specify the state file explicitly. Using this option will
also disable the use of fallback state files.
- -v
- Increase the verbosity. This option can be given multiple
times.
- -x
- Ignore file arguments which have compressed extensions.
- -z
- Discard output. Similar to redirecting the output to
/dev/null, but faster. If used in conjunction with the -f
option, only the initial output will be discarded.
FILES¶
.since
State file recording the length of the
previously displayed files. The location of the file can be set on the command
line using the
-s option. If this option is not given,
since
will check the
SINCE environment variable for the location of the state
file. If the
SINCE environment variable has not been set
since
will use the
HOME environment variable and store the information in the
file
$HOME/.since. If the
HOME variable is not set,
since
will use a
getpwuid(3) lookup. If all these fail will use the file
/tmp/since.
BUGS¶
since uses the inode of a file as its key, if that inode is recycled
since will get confused.
since is not particularly efficient
when storing or looking up the
stat(2) information. Functionality
equivalent to
since can probably be achieved with a number of trivial
shell scripts.
COPYING¶
since may only be used, distributed and modified in accordance with the
terms of the
GPL (GNU General Public License) version
3 or newer
as published by the
FSF (Free Software Foundation).
SEE ALSO¶
tail(1),
stat(2).