GSNA Question #133: Real Exam Question with Answer & Explanation

Question

Options

• Aless -g /var/adm/messages
• Btail /var/adm/messages
• Ccat /var/adm/messages
• Dtail -f /var/adm/messages

Explanation

The tail command is used to display the last few lines of a text file or piped data. It has a special command line option -f (follow) that allows a file to be monitored. Instead of displaying the last few lines and exiting, tail displays the lines and then monitors the file. As new lines are added to the file by another process, tail updates the display. This is particularly useful for monitoring log files. The following command will display the last 10 lines of messages and append new lines to the display as new lines are added to messages: tail -f /var/adm/messages Answer: B is incorrect. The tail command will display the last 10 lines (default) of the log file. Answer: C is incorrect. The concatenate (cat) command is used to display or print the contents of a file. Syntax: cat filename For example, the following command will display the contents of the /var/log/dmesg file: cat /var/log/dmesg Note: The more command is used in conjunction with the cat command to prevent scrolling of the screen while displaying the contents of a file. Answer: A is incorrect. The less command is used to view (but not change) the contents of a text file, one screen at a time. It is similar to the more command. However, it has the extended capability of allowing both forward and backward navigation through the file. Unlike most Unix text editors/viewers, less does not need to read the entire file before starting; therefore, it has faster load times with large files. The command syntax of the less command is as follows: less [options] file_name Where,

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