[Crash-utility] RFE: run crash in "help mode"

[Dave Anderson]

----- Original Message -----
> On 02/13/12 06:23, Dave Anderson wrote:
> >       -h [option]
> >       --help [option]
> >              Without  an option argument, display a crash usage
> >              help message.
> >              If the option argument is a crash command name,
> 
> I've learned how to look without seeing sometimes.  :(  Thanks!
> Interactive would be marginally easier, but not enough to make
> it worth the effort.
> 
> > And although it's undocumented, you can get a complete dump of all pages
> > by entering "crash -h all".
> 
> That would be a good sentence to add to the "--help" clause.

Yeah, I'll do that.  I forgot about that option when the man page
was overhauled recently.

> 
> > Alternatively, if you've got a browser window open, go to the "Builtin Help"
> > page of the crash whitepaper, and just click on the command you're
> > interested in:
> >
> >   http://people.redhat.com/anderson/crash_whitepaper/#HELP
> 
> _That_ is definitely nice!
> 
> Now that I'm futzing with this, another RFE or else "Request for how
> to really do it":
> 
> a "source" command.  In my environment, we've got 16 (yes, *sixteen*) loadable
> modules that need to get "mod -s MODNAME /path/to/modname.ko" -ed.
> So not being a big fan of typing, my preference would be to:
> 
>     mod | script-to-look-for-modules > mod-s-commands
>     source mod-s-commands
> 
> and presto, my .ko files are loaded.  
> So, is there an easier way, or is the "source" command reasonable?

There's 3 possibilities...

Put the mod commands in a .crashrc file in the current directory, or in
your $HOME directory, like this example:
  
  # cat .crashrc
  mod -s nfsd
  mod -s nfs
  # crash
  
  crash 6.0.3
  Copyright (C) 2002-2012  Red Hat, Inc.
  Copyright (C) 2004, 2005, 2006  IBM Corporation
  Copyright (C) 1999-2006  Hewlett-Packard Co
  Copyright (C) 2005, 2006  Fujitsu Limited
  Copyright (C) 2006, 2007  VA Linux Systems Japan K.K.
  Copyright (C) 2005  NEC Corporation
  Copyright (C) 1999, 2002, 2007  Silicon Graphics, Inc.
  Copyright (C) 1999, 2000, 2001, 2002  Mission Critical Linux, Inc.
  This program is free software, covered by the GNU General Public License,
  and you are welcome to change it and/or distribute copies of it under
  certain conditions.  Enter "help copying" to see the conditions.
  This program has absolutely no warranty.  Enter "help warranty" for details.
   
  GNU gdb (GDB) 7.3.1
  Copyright (C) 2011 Free Software Foundation, Inc.
  License GPLv3+: GNU GPL version 3 or later <http://gnu.org/licenses/gpl.html>
  This is free software: you are free to change and redistribute it.
  There is NO WARRANTY, to the extent permitted by law.  Type "show copying"
  and "show warranty" for details.
  This GDB was configured as "x86_64-unknown-linux-gnu"...
  
        KERNEL: /usr/lib/debug/lib/modules/2.6.32-70.el6.x86_64/vmlinux
      DUMPFILE: /dev/crash
          CPUS: 4
          DATE: Mon Feb 13 12:11:31 2012
        UPTIME: 58 days, 22:21:22
  LOAD AVERAGE: 3.30, 3.10, 2.96
         TASKS: 340
      NODENAME: waste.usersys.redhat.com
       RELEASE: 2.6.32-70.el6.x86_64
       VERSION: #1 SMP Wed Aug 25 10:17:53 EDT 2010
       MACHINE: x86_64  (2792 Mhz)
        MEMORY: 1 GB
           PID: 2405
       COMMAND: "crash"
          TASK: ffff88003c3e94a0  [THREAD_INFO: ffff880027f02000]
           CPU: 0
         STATE: TASK_RUNNING (ACTIVE)
  
  crash> mod -s nfsd
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa05955c0  nfsd                 302737  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfsd/nfsd.ko 
  crash> mod -s nfs
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa0619120  nfs                  348522  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfs/nfs.ko 
  crash> 
  
Note that the two mod commands above were not entered manually, but were
displayed and done automatically.  

Or do it during a crash session by putting the commands in a file,
and run the command's contents by redirecting:

  crash> !cat input
  mod -s nfsd
  mod -s nfs
  crash> < input
  crash> mod -s nfsd
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa05955c0  nfsd                 302737  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfsd/nfsd.ko 
  crash> mod -s nfs
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa0619120  nfs                  348522  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfs/nfs.ko 
  crash>

There's also the new redirection capability for individual commands, where
each line in the input file will be appended to the command line entered:

  crash> !cat input
  nfsd
  nfs
  crash> mod -s < input
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa05955c0  nfsd                 302737  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfsd/nfsd.ko 
       MODULE       NAME                   SIZE  OBJECT FILE
  ffffffffa0619120  nfs                  348522  /lib/modules/2.6.32-70.el6.x86_64/kernel/fs/nfs/nfs.ko 
  crash>

Hopefully one of the above suits your needs...

Dave