26. Several common Linux Shell functions, diff

1. Diff

1) Name

Diff-find differences between two files

Synopsis

Diff [Options] From-file to-file

Description

In the simplest case, diff compares the contents of the two files from-file and to-file.

2) Option

A single letter preceded by-, and the other of which is a long name preceded --. multiple single letter options (unless they take an argument) can be combined into a single command line word:-ac is equivalent to-a-c. long named options can be abbreviated to any unique prefix of their name. brackets ([and]) indicate that an option takes an optional argument.

(1)-A: Set all filesCompositionThis file is used to compare by line.

(2)-B ignore Spaces

-B. Ignore empty rows.

-H uses the test method to accelerate searching for large files

-I case-insensitive

-R: Compare files in the directory

-N treat nonexistent files as empty files

-U uses the uniied format. -U "Number of columns" or "-uniied =" Number of columns "to display different file content in a combined manner.

-Y use the side by side output format.

-- When left-column uses the-y parameter, if one row of the two files has the same content, only the content of the row is displayed in the left column.

-- When suppress-common-lines uses the-y parameter, only the difference is displayed.

-W columns use an output width of columns in side by side format. This parameter is used when the y parameter is used.

-T add a Tab character before each line for alignment

-P if the file to be compared is in C LanguageProgramThe function name of the difference.

-C: display all internal text and mark the differences.

-Q: only whether it is the same

3) Example

(1) diff test Test2

Starting with a smaller sign is saved in the first file, and starting with a greater sign is displayed in the second file. Letters A, D, and C indicate the attaching, deleting, and modifying Operations respectively. Diff can distinguish block and character device files and FIFO (MPS queue files) without comparing them with common files.

(2) diff-I-y-W 80 test test1

Reference

[1]Http://www.flatws.cn/article/program/shell/2011-02-23/14053.html

[2]Http://linux.die.net/man/1/diff

[3] a good explanation of the Parameters

Http://www.phpzixue.cn/detail976.shtml

Http://www.wycode.com/linux/shell/2011/0809/1404.html

[4]Http://www.isstudy.com/linux/387.html