RHCSA RHCSA Essential Command-Line Tools 2

Question 1

Which command displays the last 20 lines of a file named 'syslog'?

Accepted Answer

tail -20 syslog

Answer

The tail command with -N flag outputs the last N lines of a file.

Question 2

What does the command 'wc -l filename' report?

Accepted Answer

Number of lines in the file

Answer

The wc -l option counts and displays the number of newline characters (lines) in a file.

Question 3

Which command would you use to search for the string 'error' recursively in all files under /var/log?

Accepted Answer

grep -r 'error' /var/log

Answer

grep -r performs a recursive search through directories for a pattern.

Question 4

What is the effect of running 'sort -u file.txt'?

Accepted Answer

Sorts the file and removes duplicate lines

Answer

The sort -u option sorts lines and suppresses duplicate output lines, keeping only unique entries.

Question 5

Which sed command replaces only the FIRST occurrence of 'foo' with 'bar' on each line of input?

Accepted Answer

sed 's/foo/bar/' file

Answer

Without the g flag, sed's s command replaces only the first match on each line by default.

RHCSA Exam Practice Test