centos-shell-Special Characters

Shell wildcard characters

# notice is completely different from regular, similar to regular

　　* any of at least one character

　? Any one character

　　[ ] [] any one of the characters, the relevant character set a-Z 0-9

Shell redirection

# re-designation of system standard input, standard output, standard error output

　　Enter Redirection < <<

# number 0, can be omitted

Change the shell's input source, either terminal input or file input, to append content to the file, etc.

　　Output REDIRECT > >>

# number 1, can be omitted

REDIRECT the Shell's screen output to the specified file

> Coverage

>> Append

　　Error redirection 2> 2>>

# number 2, not omitted

REDIRECT the Shell's error output to the specified file

2> coverage

2>> Append

　　Common

Correct and Error output redirect override mode 2>&1 &>

Correct and error output redirect append mode 2>>&1 &>>

　　　# for timed tasks, shell script logs, or no concern for Shell output Redirect to/dev/null

Shell Pipeline |

The output of the previous shell as input to a command behind the pipeline

Shell escape character \

1. Precede the special single character, ignoring the character's meaning

2. The form wraps, the command line does not write, the other line again writes, essentially is a line command

Shell single quote ' '

WYSIWYG, ignoring the meaning of all special characters in a character

Shell double Quote ""

Special characters are escaped

Shell anti-quote ' '

Try to run the returned output with the characters in the command mode, and the same as $ ()

Catalog file Related

　　/ root directory

　　CD Command related

The current directory .

Parent Directory :

Current User home directory ~

Last working directory -

　　{} Create files, directories, backup files, rename using

From a certain start to an end, the range can be an integer greater than 0 or a-Z-A-range {start}. End

Touch {A.. C}.txt

Add a suffix to a file or directory to back up files or rename files or directories {, name}

MV Scripts{,.new}

　　

Shell History Command related

　　; Split two commands

　! Call History Command, Federated history Use, can be directly historical command number execution or command name execution, command name execution then execute the latest command

User-related

　　# Super User

　　$ Normal user, also gets the value of the corresponding variable in the user shell

centos-shell-Special Characters