tail
is a command-line utility that allows you to display the last part of files. It is a highly versatile tool, commonly used in system administration and cybersecurity to monitor log files, trace errors, and observe real-time system activities. This utility is available by default on most Unix-based operating systems, such as Linux and macOS.
The basic syntax for the tail
command is:
tail [options] [file_name]
options
: Flags that modify the behavior of the command.file_name
: The name of the file you want to display.Some common options in tail
include:
-n [lines]
: Output the last [lines]
lines, instead of the default last 10 lines.-f
: Follow the file as it grows, displaying new content in real time.-F
: Similar to -f
, but also tries to keep the file open if it’s removed, can’t be accessed or replaced-q
: Quiet mode - never output headers with file names-s [seconds]
: Sleep for approximately [seconds]
between iterations. This is applicable with -f
flag.tail file_name
tail -n 50 file_name
tail -f log_file
tail -f log_file1 log_file2 log_file3
tail
is often used by cybersecurity professionals to analyze log files, trace errors, and monitor system activities. Some common use cases include:
/var/log/auth.log
file in real time:tail -f /var/log/auth.log
tail -n 50 /var/log/apache2/access.log
tail -f /var/log/syslog
In summary, tail
is a powerful and versatile command-line utility that proves to be an invaluable resource for system administrators and cybersecurity professionals, providing real-time monitoring and analysis of log files and system activities.