2.1 KiB
Executable File
2.1 KiB
Executable File
The tail command
The tail command prints the last ten lines of a file.
Example:
tail filename.txt
Syntax:
tail [OPTION] [FILENAME]
Get a specific number of lines with tail:
Use the -n option with a number(should be an integer) of lines to display.
Example:
tail -n 10 foo.txt
This command will display the last ten lines of the file foo.txt.
Refresh the output on any new entry in a file
It is possible to let tail output any new line added to the file you are looking into. So, if a new line is written to the file, it will immediately be shown in your output. This can be done using the --follow or -f option. This is especially useful for monitoring log files.
Example:
tail -f foo.txt
Syntax:
tail -n <number> foo.txt
Additional Flags and their Functionalities
| Short Flag | Long Flag | Description |
|---|---|---|
-c |
--bytes=[+]NUM |
Output the last NUM bytes; or use -c +NUM to output starting with byte NUM of each file |
-f |
--follow[={name|descriptor}] |
Output appended data as the file grows; an absent option argument means 'descriptor' |
-F |
Same as --follow=name --retry | |
-n |
--lines=[+]NUM |
Output the last NUM lines, instead of the last 10; or use -n +NUM to output starting with line NUM |
--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 rename (this is the usual case of rotated log files); with inotify, this option is rarely useful |
|
--pid=PID |
with -f, terminate after process ID, PID dies | |
-q |
--quiet, --silent |
Never output headers giving file names |
| `` | --retry |
keep trying to open a file if it is inaccessible |
-s |
--sleep-interval=N |
With -f, sleep for approximately N seconds (default 1.0) between iterations; with inotify and --pid=P, check process P at least once every N seconds |
-v |
--verbose |
Always output headers giving file names |
-z |
--zero-terminated |
Line delimiter is NUL, not newline |
--help |
Display this help and exit | |
--version |
Output version information and exit |