Compaction Basic Linux------Five commands per day:

Command one:

Cat opens the contents of a file, or splicing two file contents and outputs

-N or--number the number of rows for all outputs starting from 1
-B or--number-nonblank and-n similar, except for blank lines not numbered
-S or--squeeze-blank when you encounter a blank line that has more than two consecutive lines, replace the blank line with one line
-V or--show-nonprinting

Add a line number to the Textfile1 file and enter the Textfile2 file.
Cat-n textfile1 > Textfile2

Command two:

Diff compares the differences between files.

syntax:diff [-abbcdefhilnnppqrsttuvwy][-< rows >][-c < rows >][-d < macro name >][-i < character or string >][-s < File >][-w < width >][-x < file or directory >][-x < file >][--help][--left-column][--suppress-common-line][file or directory 1][ File or directory 2]

Note:diff compares the similarities and differences of text files in a row-by-line manner. Specifies that to compare directories, diff compares files of the same file name in the directory, but does not compare subdirectories.

Parameters:
-< lines > Specifies 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< lines > or--context< lines > is the same as executing the-c-< lines > directive.
-D or--minimal use different algorithms to compare in smaller units.
-d< Macro name > or ifdef< macro name > 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< characters or Strings > or--ignore-matching-lines< characters or strings > If two files differ 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 appears only in a directory, the preset displays:
Only in directory: If file a uses the-n parameter, diff compares file A to 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< file > or--starting-file< file > compares directories, starting 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< number of columns > or--unified=< columns > displays the contents of the file differently in a merged manner.
-V or--version displays version information.
-W or--ignore-all-space ignores all whitespace characters.
-w< width > or--width< width > Specifies the width of the column when using the-y parameter.
-x< filename or directory > or--exclude< filename or directory > does not compare the file or directory specified in the option.
-x< file > or--exclude-from< file > You can save the file or directory type as a text file, and then specify the text file in =< file >.
-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.

Command three:

File identification type

Additional note: through the file directive, we are able to identify the type of the document.

Parameters
-B The file name is not displayed when the identification results are listed.
-C Displays the instruction execution process in detail to facilitate troubleshooting or analysis of the execution of the program.
-f< name File > Specify a name file with the contents of one or more file names, let file identify these files sequentially, in the format of one file name per column.
-L Displays the category of the file that the symbolic connection points to directly.
-m< Magic Digital File > Specify Magic Digital file.
-V Displays version information.
-Z try to interpret the contents of the compressed file.

Command four:

Chattr (change attribute)

Feature Description: change file properties.

syntax:chattr [-rv][-v< version number >][+/-/=< properties >][file or directory ...]

Additional Note: This directive alters the file or directory attributes stored on the ext2 file system, which have the following 8 modes:
A: Make the file or directory available for additional use only.
B: Do not update the last access time of the file or directory.
C: Compress the file or directory and store it.
D: Exclude files or directories from dumping operations.
I: Do not alter the file or directory arbitrarily.
S: Privacy delete files or directories.
S: Update files or directories instantly.
U: Remove outside of prevention.

Parameters
-R recursively handles all files and subdirectories under the specified directory.
-v< version number > set file or directory version.
-V Displays the instruction execution process.
+< Properties > Open the Item property of the file or directory.
-< Properties > Close the Item property of the file or directory.
The =< property > Specifies the Item property of the file or directory.

Command five:

Diffstat (differential status)

function Description: The statistics are displayed according to diff comparison results.

syntax:diff [-wv][-n < filename length >][-p < filename length;]

add:diffstat read the output of diff, and then count the various files to insert, delete, modify and so on difference metering.

Parameters
-n< filename length > Specifies the length of the file name, the length must be greater than or equal to the longest file name in all files.
The-p< filename length > is the same as the-n parameter, but here the < filename length > includes the path to the file.
-W Specifies the width of the field at the output.
-V Displays version information.

Compaction Basic Linux------Five commands per day: