docs/en/Development-And-Common-Documents/Novice-Must-See/Basic_Operation_Linux_Files.md

Linux file basic operations

Author: winifred

Time: 2023.3.15

1. File directory

1.1 ls command

The ls command is used to print the current directory list, and you can view file permissions (including directories, folders, and file permissions) to view directory information, etc.

Command format: ls [option] [directory name]

Common parameters:

• -a: list all files, including implied files starting with .
• -l: List file permissions, owner, file size and other information
• -t: Sort by file modification time

1.2 cd command

The cd command is used to change the current directory to the specified directory.

Command format: cd [directory name]

Common examples:

• cd /: change to the root directory
• cd ..: switch to the previous directory
• cd ~: switch to user home directory

1.3 pwd command

The pwd command is used to determine the exact location of the current directory within the file system.

Command format: pwd [option]

Common parameters:

• -P: Display the actual physical path
• -L: When the directory is a connection path, display the connection path

2. Basic file operations

2.1 Create a new file

Use the touch or vi command to create a blank file.

Common examples:

touch test.md
vi test.md

2.2 Create a new directory

Use the mkdir command to create an empty directory, and you can also specify the permission attribute to create the directory.

Common examples:

• Create an empty directory named mydir: mkdir mydir
• Create multi-level directories: mkdir -p A/B/C

2.3 Delete files/directories

Use the rm command to delete a file, use the -f parameter to force deletion, and use the -r parameter to delete a directory.

Common examples:

• Delete the test.md file: rm test.md
• Force delete test.md file: rm -f test.md
• Delete the A folder: rm -r A

2.4 Copy files/directories

Use the cp command to copy a file to the specified directory, and use the -r parameter to copy the directory.

Command format:

• Copy files: cp [filename] [directory]
• Copy directory: cp -r [filename] [directory]

Common examples:

• Copy test.md file to C folder: cp test.md /home/user/A/B/C

You need to enter the directory where the test.md file is located

• Copy A to the alphabet folder: cp -r A alphabet

2.5 Moving and renaming files

Use the mv command to move files (cut) or rename files

Command format:

• Move files: mv [source directory file] [destination directory]
• Rename file: mv [original filename] [new filename]

Common examples:

• Move the file file to the filedir directory: mv file filedir
• Rename file file1 to file2: mv file1 file2

2.6 View files

2.6.1 cat, tac command

The cat and tac commands are used to print the contents of the file to the standard output (terminal), where cat displays the number of lines in positive order, and tac displays the number of lines in reverse order.

Common examples:

• View the /etc/passwd file: cat /etc/passwd
• Show line numbers: cat -n /etc/passwd

2.6.2 more command

more is used to "read" the contents of a file. You can use Enter to scroll down, Space to print all, and q to quit.

2.6.3 head, tail command

View the first few lines and the last few lines of the file, the -n parameter is used to indicate the number of lines to view.

2.7 grep command

The grep command is used to find matching text in a file, and can accept regular expressions and wildcards, and multiple grep command options can be used to generate output in various formats.

Command format: grep [option] pattern [file]

Common examples:

• Extract the line where root appears in the /etc/passwd file: grep "root" /etc/passwd
• Extract the line that does not appear root in the /etc/passwd file: grep -v "root" /etc/passwd