Shulou(Shulou.com)06/01 Report--

The previous words

I think the front-end engineer may not need the Shell command. But when learning Git, I found that in addition to the Git command, there are a lot of Shell commands to cooperate with. Therefore, Shell commands need to be systematically studied and summarized. This article will introduce the common commands of shell in detail.

Special character

Special characters have a special meaning to shell, so don't use them as ordinary characters. Some special characters are used for regular expression matching

&; | *?'"`[] () $

{} # /\! ~

Blank character

Although RETURN, SPACE and TAB are not special characters, they have special meanings to shell.

The RETURN key is usually used to end the command line and start the execution of the command

The SPACE and TAB keys are used as delimiters on the command line

Escape character

To use special characters as ordinary characters, escape references to them

[note] the slash (/) cannot be escaped, it always represents the delimiter in the path name

The special characters can be escaped by adding a backslash (\) before the special characters. To escape two or more consecutive special characters, you must precede each character with a backslash (\)

Another way to escape special characters is to enclose them in single quotation marks ('*'), or you can enclose special characters and ordinary characters in a pair of single quotation marks.

Catalog correlation

Show directory path

[pwd] displays the current directory

[note] if you use the Windows system, in order to avoid all kinds of inexplicable problems, please make sure that the directory name (including the parent directory) does not contain Chinese

Switch directories

[cd] switch to another working directory, and the parameter direction is the path name of the directory to be specified as the new working directory.

Cd [options] [direction]

If you do not take any parameters, or use the tilde (~), change to the home directory

Use a hyphen (-) to switch to the previous working directory

Use double periods (..) To return to the directory one level up under the current directory

Create a directory

[mkdir] create a directory. If a directory with the same name already exists, it cannot be created successfully.

Mkdir [option] directory-list

Delete directory

[rmdir] Delete a directory. If it is not empty, it cannot be deleted successfully.

Rmdir directory-list

File correlation

Show all files

[ls] is similar to the dir command under dos and is used to display information about one or more files

By default, ls lists the information of files in alphabetical order of file names

Ls [options] [file-list]

Options has many options, and the common options are as follows

Ls-a displays all files, including the hidden file ls-F, adding symbols to the end of the file to indicate the file type. * indicates executable, / indicates directory, @ indicates link file ls-l lists more detailed information of each file ls-R recursively lists the contents of the subdirectory ls-t displays the files in the order of the last modification time

When file-list contains a directory, ls displays the contents of that directory

Ls mygit displays files in the mygit directory ls g* displays all files that begin with the letter g

Show file contents

[cat] displays the contents of a text file, similar to the type command under dos

Cat [options] [direction] cat file1 displays the contents of the file1 file cat file1 file2 displays the contents of the file1,file2 in turn cat file1 file2 > file3 combines the contents of the file1,file2 and then redirects (>) to the file3 file

">" is the right redirector, which means that the result of the command on the left is regarded as the input of the command on the right. If the file on the right is an existing file, its original contents will be emptied and become the command output on the left. If you want to write as an append, use the ">" redirector instead

Rewrite a file

If there is no specified file on the left side of ">", such as cat > file1, it will wait for the user to enter, and then press [Ctrl] + [d] after the input is finished. The user's input will be written to file1.

Delete a file

[rm] Delete files, similar to the del/erase command under dos

Rm [options] file-list

Options has many options, and the common options are as follows

The rm-I system will ask for confirmation before deleting the file. After the user replies y or Y, the file will really be deleted. Rm-r recursively deletes the contents of the specified directory, including all subdirectories and the directory itself rm-f and-I parameters are opposite.-f indicates the forced deletion of the file name of each file that is deleted by rm-v.

Copy a file

[cp] copy files

Cp [options] source-file destination-filecp [options] source-file-list destination-directory

Use the cp command to make a copy of a file

You can also copy one or more files to a directory using the cp command

Cp-R recursively copies a directory hierarchy that contains ordinary files

Move files or rename

[mv] rename or move a file

Mv [options] existing-file new-filenamemv [options] existing-file-list directionmv [options] existing-direction new-direction

Use the mv command to rename a file

Use the mv command to move one file to another directory

Use the mv command to move a file to another directory and rename it

You can also move directories using the mv command

Create a new file

[touch] create a new file, or change the access and modification time of the file

Touch [options] file-list

Touch is used to create a new file when the file with the same name does not exist

When a file with the same name exists, touch is used to modify the access and modification time of the file

File Advanced

Compare files

[cmp] compare two files byte by byte. If the two files are the same, cmp does not display anything; otherwise, cmp will display the number of bytes and line number corresponding to the first difference.

Cmp [options] file1 [file2 [skip1 [skip2]

Display is different

[diff] displays the difference between the two text files by line. By default, you can edit one of the files to be the same as the other according to the difference shown by diff

Diff [options] file1 file2diff [options] file1 directorydiff [options] directory file2diff [options] directory1 directory2

File1 and file2 are the pathnames of plain text files to be compared by diff. When file2 is replaced by the directory parameter, diff will look for files with the same name as file1 in the directory directory; similarly, when file1 is replaced by directory, diff will look for files with the same name as file2 in the directory directory; when two directory parameters are specified, diff will compare two files with the same simple file name in the directory1 directory as in the directory2 directory

1c1 means to change the first line of a.txt to be the same as the first line of b.txt

Statistics

[wc] displays the number of lines, words, and bytes

Wc [options] [file-list]

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