tail(1) - Linux man page

Name

Synopsis

Description

Print the last 10 lines of each FILE to standard output. With more than one FILE, precede each with a header giving the file name. With no FILE, or when
FILE is -, read standard input.

Mandatory arguments to long options are mandatory for short options too.

--retry

keep trying to open a file even if it is inaccessible when tail starts or if it becomes inaccessible later; useful when following by name, i.e., with
--follow=name

-c, --bytes=N

output the last N bytes

-f, --follow[={name|descriptor}]

output appended data as the file grows; -f, --follow, and --follow=descriptor are equivalent

-F

same as --follow=name --retry

-n, --lines=N

output the last N lines, instead of the last 10

--max-unchanged-stats=N

with --follow=name, reopen a FILE which has not changed size after N (default 5) iterations to see if it has been unlinked or renamed (this
is the usual case of rotated log files)

--pid=PID

with -f, terminate after process ID, PID dies

-q, --quiet, --silent

never output headers giving file names

-s, --sleep-interval=S

with -f, sleep for approximately S seconds (default 1.0) between iterations.

-v, --verbose

always output headers giving file names

--help

display this help and exit

--version

output version information and exit

If the first character of N (the number of bytes or lines) is a '+', print beginning with the Nth item from the start of each file, otherwise, print the
last N items in the file. N may have a multiplier suffix: b 512, k 1024, m 1024*1024.

Adopt 10 good habits




Ten good habits to adopt are:





1. Make directory trees in a single swipe.


2. Change the path; do not move the archive.


3. Combine your commands with control operators.


4. Quote variables with caution.


5. Use escape sequences to manage long input.


6. Group your commands together in a list.


7. Use xargs outside of find.


8. Know when grep should do the counting -- and when it
   should step aside.


9. Match certain fields in output, not just lines.


10. Stop piping cats.

The 10 additional good habits you should adopt are:





• Use file name completion.


• Use history expansion.


• Reuse previous arguments.


• Manage directory navigation with pushd
  and popd.
  


• Find large files.


• Create temporary files without an editor.


• Use the curl command-line utility.


• Make the most of regular expressions.


• Determine the current user.


• Process data with awk.

11.7 glob --
Unix style pathname pattern expansion

The glob module finds all the pathnames matching a specified
pattern according to the rules used by the Unix shell. No tilde
expansion is done, but *, ?, and character ranges
expressed with [] will be correctly matched. This is done by
using the os.listdir() and fnmatch.fnmatch()
functions in concert, and not by actually invoking a subshell. (For
tilde and shell variable expansion, use os.path.expanduser()
and os.path.expandvars().)

glob(

pathname)

Return a possibly-empty list of path names that match pathname,
which must be a string containing a path specification.
pathname can be either absolute (like
/usr/src/Python-1.5/Makefile) or relative (like
../../Tools/*/*.gif), and can contain shell-style wildcards.
Broken symlinks are included in the results (as in the shell).

iglob(

pathname)

Return an iterator which yields the same values as glob()
without actually storing them all simultaneously.

New in version 2.5.

For example, consider a directory containing only the following files:
1.gif, 2.txt, and card.gif. glob()
will produce the following results. Notice how any leading components
of the path are preserved.

>>> import glob
>>> glob.glob('./[0-9].*')
['./1.gif', './2.txt']
>>> glob.glob('*.gif')
['1.gif', 'card.gif']
>>> glob.glob('?.gif')
['1.gif']

3. ``Putting'' an entire directory

ucsu>  scp -r  research  newton:MyRsrch/09/

copy directory ``research'' recursively (i.e., the directory
and all its contents) from ucsu
into a new directory
``MyRsrch/09/'' in your home directory on newton

(the directory ``MyRsrch'' must already exist).

Sometimes a better alternative is to create a
tar file, then copy over

only that single tar file
and unpack it on the remote host.

4. ``Getting'' an entire directory

ucsu>  scp -r  smithj@euclid.ucla.edu:MyRsrch/09 ./r9/

copy directory ``MyRsrch/09/'' recursively (i.e., the directory
and all its contents) from
euclid.ucla.edu (where you are
"smithj" into a new directory ``r9/'' in your current
working directory on ucsu.

Sometimes a better alternative is to ssh to the remote
computer, bundle the
files you want into a single
tar file, scp that file over,
and unpack it where you want the files.