C、Processes and the shell
1、 what processes are running?
the ps command
the pstree/ptree command
2、 Whet are system calls?
3、 Creating processes
D、 Environment and inheritance
1、 ownership and permissions
2、 the file creation mask
3、 changing permissions and ownership
chmod command
chown command
4、 the working directory
5、 variables
E、redirection and pipes
1、 file descriptors (0:标准输入 1:标准输出 2:标准错误输出)
2、 redirection
3、 pipes
F、 the shell and signals
A. the signal can be ignored
B. the processes can be stopped
C. the processes can be continued
D. the signal can be caught by a function defined in the program.
G、 Executing commands from scripts
Go into your favorite editor and type in a set of unix/Linux commands, one per line.
Indicate what shell you want by placing the pathname of the shell after the #! On the
first line.
Save your file and turn on the execute permissions so that you can run it.
Execute your program just as you would any other unix/Linux command.
二、 Shell programming Quick Start
1、 Taking a peek at shell scripts
A. The c shell and TC shell emulate the c language syntax whereas Bourne shell is
based on an older programming language called Algol.