tr (translate characters) in Linux CLI - Cheat Sheet & Quick Revision

Recall & Review

beginner

What does the tr command do in Linux?

The tr command translates or replaces characters from input text. It reads from standard input and writes to standard output.

beginner

How do you use tr to change all lowercase letters to uppercase?

Use tr 'a-z' 'A-Z'. This replaces every lowercase letter with its uppercase version.

intermediate

What happens if the second set of characters in tr is shorter than the first?

The last character of the second set is repeated to match the length of the first set.

beginner

How can you delete characters using tr?

Use the -d option with the characters to delete. For example, tr -d 'aeiou' deletes vowels.

intermediate

Explain the use of tr -s option.

The -s option squeezes repeated characters into one. For example, tr -s ' ' replaces multiple spaces with a single space.

What does tr '0-9' ' ' do?

A Reverses digits

B Deletes digits

C Converts digits to asterisks

D Replaces digits with spaces

The command replaces all digits (0-9) with spaces.

Which option deletes characters in tr?

A -d

B -s

C -c

D -r

The -d option deletes specified characters.

How do you convert uppercase letters to lowercase using tr?

A tr 'A-Z' 'a-z'

B tr 'a-z' 'A-Z'

C tr '0-9' 'a-z'

D tr -d 'A-Z'

Use tr 'A-Z' 'a-z' to convert uppercase to lowercase.

What does tr -s '\n' do?

A Deletes newlines

B Replaces newlines with spaces

C Squeezes multiple newlines into one

D Duplicates newlines

The -s option squeezes repeated newlines into a single newline.

If the second set is shorter in tr, what happens?

A Error occurs

B Second set is repeated to match first

C Characters are deleted

D No change happens

The last character of the second set repeats to match the first set's length.

Describe how to use tr to replace all vowels with asterisks in a text.

Think about specifying vowels as first set and '*' as second set.

Explain the difference between tr -d and tr -s options with examples.

Consider how each option changes the input text differently.