Detailed explanation of the use of sort command in Linux

sort is a very commonly used command in Linux. It treats each line of the file as a unit and compares it with each other. The comparison principle is from the first character backward and press ASCII in sequence. The code values ​​are compared, and finally they are output in ascending order.

There is a file test here, the content is:

8723 23423
321324 213432
23 234
123 231
234 1234
654 345234

1. The -t option and -k option of sort

sort provides the -t option, which can be set later separator, -k to specify the number of columns.

Sort the first column

sort test

Sort the second column

sort -k 2 test

If you change the content of the test file to:

8723,23423
321324,213432
23,234
123,231
234,1234
654,345234

If you want to The second column is sorted by size

sort -t "," -k 2 test

If there is no -t option, it is the default space or tab key, so the -t option is not used above.

2. Use the -r option to sort in reverse order

The default sorting method of sort is ascending order, and the -r parameter is changed to descending order

sort -r test

Output result:

8723 23423
654 345234
321324 213432
234 1234
23 234
123 231

3. The -n option of sort

sort compares by ASCII code value by default, so if you look at the results in 2 above, you will find that 8723 is ranked first compared to 321324. So how do we make it sort by numerical size? This is when the -n parameter comes into play.

sort -n test

Output result:

23 234
123 231
234 1234
654 345234
8723 23423
321324 213432

sort -rn test

Output result:

321324 213432
8723 23423
654 345234
234 1234
123 231
23 234

Attachment: Detailed explanation of sort command parameters

-f Convert all lowercase letters to uppercase letters. Compare, that is, ignore case

-c Check whether the file has been sorted. If it is out of order, output the relevant information of the first out-of-order line, and finally return 1

-C Check whether the files are sorted. If they are out of order, the content will not be output and only 1 will be returned.

-M Sort by month, such as JAN is less than FEB, etc.

-b Ignore each All blank parts in front of a line are compared starting from the first visible character

-u Remove duplicate lines from the output line without changing the content of the file itself

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