tail
Last Updated on Sunday, 19 December 2010 10:56
| Article Index |
|---|
| 1. Name |
| 2. Synopsis |
| 3. Frequently used options |
| 4. Examples |
1. Name
tail [man page] - output the last part of files
2. Synopsis
tail [OPTION]... [FILE]...
3. Frequently used options
-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
-n, --lines=N
output the last N lines, instead of the last 10
4. Examples
Lets create sample file. This file will contain names of all directories in /var/. We can also number each line for better overview.
for f in $( ls /var/ ); do echo $f; done | nl > file1
By default a tail command displays last 10 lines of given file.
tail
To display just last 3 lines from this file we use -n option:
tail -n 3 file1
Moreover the same output can be produced by command:
tail -3 file1
To use tail command on byte level we can use -c option. This option will make tail command to display last 4 bytes (4 characters) if a given file:
tail -c 4 file1
If you wonder why we can see only 3 characters, use od command to see where the 4th byte is:
tail -c 4 file1 | od -a
Another very useful option for tail command is -f. This option will continuously display a file as it is dynamically edited by another process. This option is very useful for watching log files.
tail -f /var/log/syslog
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