Linux pipeline command note, linux pipeline command note

Linux pipeline command note, linux pipeline command note

Pipeline command (pipe)

Use "|" to define the symbol

Pipeline commands must be able to receive data from the previous command into standard input to continue processing

1. Select the command: cut, grep. Analyze the data and retrieve what we want.

-Cut refers to a piece of information that is "cut" and taken out in the unit of "row.

Cut-d 'separator '-f fields is used for delimiter classes (-f fields retrieves the meaning of the nth segment-f 5 fifth segment-f 3,5 third and fifth segments)

The cut-c character range is used to arrange neatly and formatted Information (-c range, which extracts fixed cut-c 12-20 in characters)

 

-Gerp analyzes a line of information, including the required information, and takes the entire line out.

Grep [-acinv] [-- color = auto] 'query string' filename

-A: query the data of a binary file as a text file.

-C: calculates the number of times a string is found.

-I: case insensitive

-N: Output row number

-- Color = auto: color of keywords

Example: last | grep 'root'

Last | grep 'root' | cut-d' f1

2. Sorting command sort, wc, uniq

-Sort is sorted based on different data types.

Sort [-fbMnrtuk] [file or stdin] (-n uses pure numeric sorting-r reverse sorting-only one row of data with the same u-t separator-k interval)

Example: cat/etc/passwd | sort-t': '-k 3-n

-Uniq repeated Data Processing

Uniq [ic]

-I case-insensitive

-C for counting

Example: last | cut-d ''-f1 | sort | uniq

-Number of lines, characters, and words in the wc statistics File

Wc [-lwm]

-L: Line

-W: Word

-M: character

Example: cat/etc/man. config | wc

3. Dual-targeting tee transfers a copy of the standard out to the file and transfers the same data to the screen for processing.

Example: ls-l/home | tee ~ /Homefile | more

4. character conversion commands: tr, col, join, paste, expand

-Tr: delete or replace the text in the information.

Tr [-ds] set1 (-d Delete-s replace)

Example: last | tr' [a-z] ''[A-Z]''

Cat/etc/passwd | tr-d ':'

-Col [-xb]: replace tab with Space

-Join is used to process data between two files. Before using join, sort by sort first.

Join [-ti12] file1 file2

-T: Data delimiter. The default value is space.

Example: join-t': '-1 4/etc/paswd-2 3/etc/group

-Split cut command

Split [-bl] file PREFIX

-B: size of the file to be cut

-L cut by number of rows

Example: ls-al/| split-l 10-lsroot

Wc-l lsroot *