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Why does UNIQ print only the unique lines?
That doesn’t seem to be either the unique lines nor the duplicate lines. Right—because this is the first quirk. If you run uniq with no options, it behaves as though you used the -u (unique lines) option. This tells uniq to print only the unique lines from the file.
What are the options for the uniq command?
Options For uniq Command: -c – -count : It tells how many times a line was repeated by displaying a number as a prefix with the line. -d – -repeated : It only prints the repeated lines and not the lines which aren’t repeated. none : Do not delimit duplicate lines at all. This is the default.
How to use Uniq in a text file?
Suppose you have a text file named kt.txt which contains repeated lines that needs to be omitted. This can simply be done with uniq. //displaying contents of kt.txt// $cat kt.txt I love music. I love music. I love music. I love music of Kartik. I love music of Kartik. Thanks. Now, as we can see that the above file contains multiple duplicate lines.
How to count number of duplicates in UNIQ?
Counting Duplicates. You can use the -c (count) option to print the number of times each line appears in a file. Type the following command: uniq -c sorted.txt | less. Each line begins with the number of times that line appears in the file. However, you’ll notice the first line is blank. This tells you there are five blank lines in the file.
Why do I have to use sort every time I use UNIQ?
Because the first time a line appears in the file, it’s unique; only the subsequent entries are duplicates. You can think of it as listing the first occurrence of each unique line. Let’s use sort again and redirect the output into a new file. This way, we don’t have to use sort in every command.
Is there way to skip lines in UNIQ?
The lines are detected as duplicates and counted correctly. Notice the line numbers displayed are those of the first occurrence of each duplicate. You can also skip fields (a run of characters and some white space) instead of characters. We’ll use the -f (fields) option to tell uniq which fields to ignore.
When do you print who in who command?
If given two non-option arguments, who prints only the entry for the user running it preceded by the hostname. Traditionally, the two arguments given are ‘am i’, as in ‘who am i’.
How to use who command to list users?
who command options Option Description -a Same as -b -d –login -p -r -t -T -u -b Time of last system boot -d Print dead processes -H Print line of column headings