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Full Discussion: Loops
Top Forums Shell Programming and Scripting Loops Post 302559345 by Chubler_XL on Monday 26th of September 2011 10:38:18 PM
Old 09-26-2011
opt 2>/dev/null this is just redirecting anything output to stderr (typically getopts will print some sort of message about illegal options eg "getopts: -i option unknown" to sterr). For example:
Code:
$ cat opt_eg
getopts p: opt 
echo opt is $opt
getopts p: opt 2> /dev/null
echo opt is still $opt
 
$ ./opt_eg -j
./opt_eg: illegal option -- j
opt is ?
opt is still ?

This program just throws away the error message from getopts and calls showUsage instead. There is a good chance that showUsage is an internal function to this script.

getopts sets $opt to ? if an invalid arugment is detected, the *) clause of the case statement picks up any value not matched by the other case clauses so it grabs ?, or any other value not listed above and calls showUsage.

The assumption is that showUsage would then exit (probably with some non-zero exit code) otherwise you will get usage output listed for every invalid option passed to the script.
Last edited by Chubler_XL; 09-26-2011 at 11:45 PM..
This User Gave Thanks to Chubler_XL For This Post:
pdathu
 

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LEARN ABOUT CENTOS

ipmish

openipmish(1)						 Shell interface to an IPMI system					     openipmish(1)

NAME

       openipmish - Shell interface to an IPMI system

SYNOPSIS

       openipmish [option]

DESCRIPTION

       The openipmish is a command interpreter that gives the full power of the OpenIPMI library to a user-level command language.  It is designed
       so it can easily be driven with a scripting language like TCL, it has well-formed output.

       openipmish starts up with no connections or anything of that nature.  You must enter commands to make connections to domains.

OPTIONS

       --dmsg Turn on message debugging, this will dump all messages to debug log output.

       --drawmsg
	      Turn on raw message debugging, this will dump all low-level messages to debug log output.  This differs from normal  message  debug-
	      ging in that all protocol messages are also dumped, not just IPMI messages.

       --dmem Turn  on	memory debugging, this will cause memory allocation and deallocations to be checked.  When the program terminates, it will
	      dump all memory that was not properly freed (leaked).

       --dmsgerr
	      Turn on printing out low-level message errors.

       --dlock
	      Turn on lock debugging, this will check lock operations to make sure that locks are help in all the proper places and make sure that
	      locks are properly nested.

       -x <string>, --execute <string>
	      Execute the given string at startup.  This may be entered multiple times for multiple commands.

       --glib Use glib for the OS handler.

       --snmp Enable the SNMP trap handler.  openipmish must be compiled with SNMP code enabled for this option to be available.

       --help Help output

COMMANDS

       openipmish  follows  the  standard  command syntax defined in ipmi_cmdlang(7).  See that for the details on most commands.  The IPMI manual
       that comes with OpenIPMI will also be quite handy.

       openipmish defines some commands that are not in the standard command language.	These are:

       read   Read and execute commands from the given file.

       exit   Quit

       redisp_cmd on|off
	      Normally, openipmish redisplays the command line when an event comes in.	This is nice for interactive use, but bad  for	scripting.
	      This lets you turn that function on and off.

SEE ALSO

       ipmi_cmdlang(7), ipmi_ui(1)

KNOWN PROBLEMS

       None

AUTHOR

       Corey Minyard <cminyard@mvista.org>

OpenIPMI							     05/13/03							     openipmish(1)
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