Linux Learning Record-variables

Source: Internet
Author: User

Local variables

Varname=value scope for the entire bash process

Local variables

Local Varname=value scope is the current code snippet

Environment variables

Export Varname=value scope is the current shell process and its child processes

Positional variables


Special variables

$? Previous command execution status return value

echo $?

Two return values for execution results (0-255)

0 performing the correct

1-255 Execution Errors

Undo Variable

unset varname

View current variables


View environment variables in the current shell






c= $A + $B

Echo $C


Script: The stack of commands, according to the actual requirements, combined with the command flow control mechanism to implement the source program.

Shebang: Magic number


Linux Learning Record-variables

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