Shell basic Commands

Command line and Shell: the command line refers to the interface that provides user input, which itself simply accepts input and then passes the command to the command interpreter, which is the shell.

Note: The command line and file for Linux are case-sensitive

Ii. Common Commands

1 $ cd/     # #进入根目录2 $ cd/home # #进入用户主目录3 $ ls       # #列出文件和目录
4 $ ls-f    the ##-f option will be appended/after each directory, followed by * After the executable file, with the link file appended with @. This option is useful for some terminals where colors cannot be displayed
5 $ ls-a    # #显示所有文件, including hidden files starting with., command options can be combined, using multiple options, such as: LS-AF
6 $ ls-l    # #显示文件属性, LS followed by the path name, you can view the files in that subdirectory, for example: ls/etc/init.d/

There are a total of 8 different information columns, from left to right, in turn:

• Permission flags for files
• Number of links to the file
• User name of the file owner
• The user group group name where the user is located
• File size
• Date of last modification
• Time of last modification
• Filename

7 $ cat-n File name 1 file name 2  # #查看文本文件 to view multiple files simultaneously, the-N option to display line numbers
8 $ More file name  # #按页显示文件, press SPACEBAR to turn down a page, press Eenter to scroll down one line, press the Q key to exit
9 $ head/tail-n 2 File name 1 file name 2 # #显示文件的开头或结尾,-n Specify the number of rows to display
$ less/boot/gurb/gurb.cfg # #查看文本文件, press the SPACEBAR to page down, press the B key to page UP, search for a string in the file can use "/" with what to find, press the Q key to exit. With parameter-m, you can display more text information
$ grep String file name 1 file name 2 # #查找文件内容, if the string contains spaces, you must enclose the space in a single quotation mark. For example: grep ' Red Hat ' stack.h
$ find/etc/-name init.d-type-d-print # #查找文件, type can be found according to file type, there are several types

Parameters	Meaning	Parameters	Meaning
B	Block device files	F	Normal file
C	Character device files	P	Named pipes
D	Catalog files	L	Symbolic Links

$ find/usr/bin-type f-atime +100-print # #查找最近100天内没有使用过的命令即查找最后一次使用在100天或100天以前的命令
$ find. -type f-mtine-1  # #查找在当前目录下最近一天内修改过的文件
$ locate *.doc  
$ whereis-b Find # #whereis主要用于查找程序文件 and provides the file binary executable file, source code file, user manual of the storage path
$ who  # #查找当前系统中登陆用户
$ Whoani  # #查找用户自己身份
$ uname # #显示当前系统版本信息,-a option displays all useful information for the current system,-R displays kernel version information
$ man Find  # #获取命令帮助信息

Three, wildcard characters

1. "*" to match strings of any length in the file name

2, "? "To match a single character

3, "[]" to match all occurrences of the character in square brackets

Shell basic Commands