Diff of Linux commands

1. Command format:

diff[parameter [file 1 or directory 1][file 2 or directory 2]

2. Command function:

The diff command can compare individual files or directory contents. If you specify that the comparison is a file, it is only valid if the input is a text file. Compare the similarities and differences of text files in a row-by-line manner. If you specify a table of contents, the diff command compares a text file with the same name in two directories. Lists the different binaries, common subdirectories, and files that appear only in one directory.

3. Command parameters:

-Specify how many lines of text to display. This parameter must be used in conjunction with the-C or-u parameter.

The-A or--text diff preset will only compare text files line by row.

-B or--ignore-space-change do not check for differences in whitespace characters.

-B or--ignore-blank-lines does not check for blank lines.

-C Displays all the text and marks the difference.

-C or--context is the same as executing the "-c-" directive.

-D or--minimal use different algorithms to compare in smaller units.

-D or ifdef the output format of this parameter is available for the predecessor Processor macro.

-E or--ed the output format of this parameter is available for the ed script file.

The-f or-forward-ed output is formatted like an ED script file, but is displayed differently in the order of the original files.

-h or--speed-large-files can speed up when comparing large files.

-L or--ignore-matching-lines if two files are different in a few lines, and these lines both contain the characters or strings specified in the option, the differences between the two files are not displayed.

-I or--ignore-case do not check for differences in case.

-L or--paginate the results to the PR program for paging.

-N or--rcs displays the comparison results in RCS format.

-N or--new-file when comparing directories, if file a only appears in a directory, the preset will display: Only in directory: file A If you use the-n parameter, diff will compare file A with a blank file.

-P If the file is compared to a C language code file, the name of the function where the difference is displayed.

-P or--unidirectional-new-file is similar to-N, but this file is compared to a blank file only if the second directory contains a file that is not in the first directory.

-Q or--brief display only if there is no difference, no detailed information is displayed.

-R or--recursive to compare files in subdirectories.

-S or--report-identical-files if no differences are found, the message is still displayed.

-S or--starting-file when comparing directories, start comparing from the specified file.

-T or--expand-tabs expands the tab character when it is output.

-T or--initial-tab the tab character before each line to align.

-u,-u or--unified= displays the different contents of the file in a merged manner.

-V or--version displays version information.

-W or--ignore-all-space ignores all whitespace characters.

-W or--width specifies the column width when using the-y parameter.

-X or--exclude does not compare the files or directories specified in the options.

-X or--exclude-from you can save the file or directory type as a text file, and then specify the text file in =.

-Y or--side-by-side displays the similarities and differences of the files in a parallel manner.

--help display Help.

--left-column when using the-y parameter, if the contents of one row of two files are the same, the contents of that row are displayed only in the field on the left.

--suppress-common-lines displays only the differences when using the-y parameter.

Summary:diff is generally used to compare the contents of two different files, such as diff file1 File2. So how do you figure out what's new in file1 or relative file2?

1> diff 1.txt 2.txt-y w > 3.txt

-Y is a side-by-side display of the similarities and differences of the file,-W is the specified column width

2> grep-e ' <|\| ' 3.txt

< in diff, what's new in file1 relative to File2

| In diff, it's the modified content.

When we use the grep command here, we use the escape character ' \ '.

Reference article: http://www.cnblogs.com/peida/archive/2012/12/12/2814048.html

Diff of Linux commands