Linux command head, tail, tr, sort, uniq, grep

head [filename]head-n [filename] first one  lines  head-c [filename]  

Head defaults to show the first 10 rows.

tail [filename]tail-n [filename], last  lines  tail-c [filename], last  characters  

If the 第10-22 line to display text can be used:

1 head-n22 | Tail-n12

The use of TR is:

$ tr [OPTION] SET1 [SET2]

If both SET1 and SET2 are given, and option is not-D, then the elements in the first collection are replaced with the elements in the second collection.

$ TR A-Z a-zthegeekstuffthegeekstuff

If you need to replace the space with a tab, if there are contiguous spaces, you need to add the-s option, otherwise the default is to replace each space with a tab:

$ echo "This was for   testing" | tr-s [: space:] ' \ t ' thisisfortesting

If you want to delete an element, you can use (such as deleting all numbers):

$ echo "My username is 432234" | TR-D [:d igit:]my username is

If you need to remove characters other than numbers, you can use the-C option:

$ echo "My username is 432234" | TR-CD [:d igit:]432234

If you want to merge all the rows of a file into one line, you can use:

$ Tr-s ' \ n ' < file.txt

Sort has several common options:

-N Sort by number

-R Reverse Order

-K m,n sorted by M-n Field

-t change the file delimiter

To sort a tab-delimited text by a second field, you can use:

$ sort-k2,2-t $ ' \ t ' phonebook  Doe,    John555-1234 Fogarty,    Suzie555-2314 Doe, jane< c6/>555-3214 Avery, Cory    555-4132 Smith, Brett    555-4321

The tab is represented here with $ ' \ t '

Several common options for command Uniq are:

-C output Number of consecutive occurrences per line

-D outputs contiguous rows only once for rows that occur more than once

The difference between-D and-D is that the full output of the qualifying row

-U only outputs rows that do not appear consecutively

-I ignores case when comparing

-W N compares only the first n characters

-F N ignores comparison of top N filed

-S n ignores comparison of the first n characters

grep Common methods:

If you are looking for a string in a file, you can use:

grep "literal_string" filename

If the specified string is found in multiple files:

grep "string" File_pattern

-I option ignores case

To find multiple strings in a file:

grep "REGEX" filename

The-w option is used to find only the specified word, ignoring word as a string

-c option to see the number of occurrences

The-v option is used to output rows that do not appear with the specified string

The-e option can be used to specify multiple strings:

$ grep-v-E "a"-E "B"-E "C" test-file.txt

The-l (lowercase l) option is used to output the file name that contains the specified string:

 This demo_*demo_filedemo_file1

In addition, there are options such as-a,-b,-c.

Linux command head, tail, tr, sort, uniq, grep