CompTIA Linux+ Linux GNU and Unix Commands Flashcards

What is the purpose of the 'tee' command in a pipeline?

Answer: Writes output to both a file and stdout simultaneously

tee reads from stdin and writes to both stdout and one or more files at the same time.

Which command displays the inode number of a file?

Answer: ls -i filename

ls -i displays the inode number for each listed file.

A user runs 'ps aux | grep nginx'. What does the 'x' flag in 'aux' do?

Answer: Shows processes without a controlling terminal

The x flag shows processes not attached to a terminal, including daemons like nginx.

Which command replaces every occurrence of 'foo' with 'bar' in a file using sed?

Answer: sed 's/foo/bar/g' file.txt

The g flag at the end of the sed substitution command applies the replacement globally on each line.

What does 'xargs' primarily do when used in a pipeline?

Answer: Converts stdin lines into command-line arguments

xargs reads items from stdin and passes them as arguments to a specified command.

Which command shows real-time system resource usage updated every second?

Answer: top

top provides an interactive real-time view of running processes and system resource usage.

What does the command 'cut -d: -f1 /etc/passwd' extract?

Answer: The username field from each line

cut -d: uses colon as delimiter and -f1 selects the first field, which is the username in /etc/passwd.