1. packing compression and name search order
tar command:
Gzip compressed file format for the name .tar.gz archive tar -czvf
NOTE: c compression; Z is Gzip compression; V compression; target file F
Extracting Gzip file format tar -xzvf codecs package names .tar.gz -C / etc
Note: x decompression; Z is Gzip decompression; V decompression process; target file F; C compression specified directory
Bzip2 compressed file format for the tar -cjvf .tar.bz2 archive name
Note: c compression; j is compressed with bzip2; v compression; f target file
Extracting Gzip file format tar -xjvf codecs package names .tar.bz2 -C / etc
Note: x decompression; j is bzip2 decompression; v decompression process; f target file; C compression specified directory
grep command:
It used to perform a keyword search the contents of files in the file
Format: grep -n keyword file
Note: -n is the line number
find command:
It is a comprehensive file search
find search path parameters search criteria
2. output redirection:
Format: command> file (empty write)
Format: command >> file (additional writing)
Format: command 2> file (empty write error)
Format: 2 >> command file (additional writing error)
Format: command &> file (All Clear written)
Format: Command & >> file (all additional writing)
3. Pipeline operators:
The previous command is supposed to be output to the standard output data after the normal standard screen as a command
Format: Command | command
4. instruction line communication Hythe
* Represents matching zero or more characters
? Represents the match is a character
[0-9] represents a single numeric characters match
Representative [az] matches a single alphabetic character
The escape character
The backslash (\): the variable behind a backslash into a simple string.
Single quotation marks ( ''): wherein all variables escaped as a simple string.
Double quotes ( ""): wherein the variable attributes retained without escaping.
Backtick ( ``): the return result executes the commands.
6. environment variables:
Commands are divided into:
a. + path name
b.alias alias
c. builtin (specific gravity 0.01%)
d. external command (specific gravity 99.9%)
And most of the time the user input is an external command, you can use the "type the command name" to determine the order entered by the user is an internal command or external command.
