Linux Text Processing & Editors 2

Question 1

What does `cut -d: -f1 /etc/passwd` do?

Accepted Answer

Extracts the first colon-delimited field from each line

Answer

cut -d: sets the delimiter to colon and -f1 extracts the first field, which is the username in /etc/passwd.

Question 2

Which command translates all lowercase letters to uppercase from stdin?

Accepted Answer

tr 'a-z' 'A-Z'

Answer

The tr command translates characters; 'a-z' specifies the source character range and 'A-Z' specifies the destination range.

Question 3

What does `uniq -c` do?

Accepted Answer

Prefixes each line with the count of consecutive occurrences

Answer

uniq -c prefixes each output line with the number of times that consecutive line appeared in the input.

Question 4

What does the `tee` command do?

Accepted Answer

Reads from stdin and writes to both stdout and a file simultaneously

Answer

tee reads from standard input and writes simultaneously to standard output and to one or more files, like a T-shaped pipe fitting.

Question 5

Which command shows the differences between two text files line by line?

Accepted Answer

diff

Answer

diff compares two files line by line and shows exactly what changes would make the first file identical to the second.

Linux Practice Test