HackerRank 'Uniq' Command #2 problem solution

In this HackerRank 'Uniq' Command #2 problem solution In this challenge, we practice using the uniq command to eliminate consecutive repetitions of a line when a text file is piped through it.

Given a text file, count the number of times each line repeats itself. Only consider consecutive repetitions. Display the space-separated count and line, respectively. There shouldn't be any leading or trailing spaces. Please note that the uniq -c-command by itself will generate the output in a different format than the one expected here.

Explanation

Sample Input

00

00

01

01

00

00

02

02

03

aa

aa

aa

Sample Output

2 00

2 01

2 00

2 02

1 03

3 aa

Explanation

00 is repeated twice

01 is repeated twice

00 is repeated twice

02 is repeated twice

03 occurs once

aa is repeated thrice

Problem solution.

uniq -c | tr -s " " | awk '$1=$1'

Second solution.

uniq -c | tr -s ' ' | cut -c2-

Third solution.

uniq -c | sed -e 's/^ \+//g'

Fourth solution.

uniq -c | sed -r 's/\s*(.*?)\s*$/\1/'