第149页 | Learning the Bash Shell | 阅读 ‧ 电子书库

Subshell Inheritance

The most important things you need to know about subshells are what characteristics they get, or inherit, from their parents. These are as follows:

 

The current directoryEnvironment variablesStandard input, output, and error, plus any other open file descriptorsSignals that are ignored

Just as important are the things that a subshell does not inherit from its parent:

 

Shell variables, except environment variables and those defined in the environment file (usually .bashrc)Handling of signals that are not ignored

We covered some of this in Chapter 3, but these points are common sources of confusion, so they bear repeating.