Embedded Systems Firmware Demystified (With CD-ROM)

The front end of the command-line processor, called docommand() , takes as its arguments the command-line string and a verbosity level. MicroMonitor uses the verbosity levels for debugging scripts. There are three levels of verbosity :

• zero verbosity

• print the incoming line as it is fed to docommand()

• print the line after shell variables and symbols have been converted

All of the command-line processing is handled in the docommand() function prior to passing control to the command-specific function. This processing includes:

• making a copy of the incoming command-line string

• expanding shell variables and symbols

• breaking up the string into its individual white-space delimited tokens

• preparing for command-line redirection

• verifying that the first token is a valid command in the command list

• providing user -level verification