Linux personal study notes (editing)

1> bash background running: Add &

2>! Command Bash History mechanism, repeated execution of History commands.

3> test is equivalent to []

4 >$? Stores the return values of functions and commands.
$ # Total Number of participants saved.

5> parameter passing is common in Linux bash commands and functions.
Eg: Command para1 para2...
Function para1 para2...

6> before the mail service in Ubuntu is used, you need to install two services.Program,
Sudo apt-Get install heirloom-mailx
Sudo apt-Get install sendmail
For example, mail root @ mycomputer
Enter the email content, press Ctrl + D, and end the input.
Press Ctrl + C to exit the service.
Read mail: Mail
Enter a number to indicate the email Collation for reading.
Enter Q to exit.

--> To be continued