2019-08-25
# Variable is set to rule
- variable name and variable content = connection with a number
- equal on both sides can not be directly hit space
- variable names only letters and numbers, but must begin with a letter
- variable contents can be used if there are spaces '' or '' with the contents of the variable combine EG: var = "Shell IS $ Good" (double quote will be considered variable value $ Good; If you want the variable to the original value, need to use single quotation marks)
-! You can use \ to escape special characters, will [Enter], $, \, spaces, and other characters become general
- the way if you need to use the information provided by other commands, you can use single quotes (note that the key is left keyboard 1) `uname -r` or $ () are eg: $ (uname -r)
- to increase the content of the variable, the variable name may be used, or $ Name $ {variable} Content accumulated
- default variable uppercase characters, lowercase may be used provided their own, in order to distinguish Analyzing
- Cancel unset variables can use the variable name eg: unset $ Good