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DDB(8) FreeBSD System Manager's Manual DDB(8) NAME ddb -- configure DDB kernel debugger properties SYNOPSIS ddb capture [-M -core] [-N -system] print ddb capture [-M -core] [-N -system] status ddb script scriptname ddb script scriptname=script ddb scripts ddb unscript scriptname ddb pathname DESCRIPTION The ddb utility configures certain aspects of the ddb(4) kernel debugger from user space that are not configured at compile-time or easily via sysctl(8) MIB entries. To ease configuration, commands can be put in a file which is processed using ddb as shown in the last synopsis line. An absolute pathname must be used. The file will be read line by line and applied as arguments to the ddb utility. Whitespace at the beginning of lines will be ignored as will lines where the first non-whitespace character is `#'. OUTPUT CAPTURE The ddb utility can be used to extract the contents of the ddb(4) output capture buffer of the current live kernel, or from the crash dump of a kernel on disk. The following debugger commands are available from the command line: capture [-M core] [-N system] print Print the current contents of the ddb(4) output capture buffer. capture [-M core] [-N system] status Print the current status of the ddb(4) output capture buffer. SCRIPTING The ddb utility can be used to configure aspects of ddb(4) scripting from user space; scripting support is described in more detail in ddb(4). Each of the debugger commands is available from the command line: script scriptname Print the script named scriptname. script scriptname=script Define a script named scriptname. As many scripts contain char- acters interpreted in special ways by the shell, it is advisable to enclose script in quotes. scripts List currently defined scripts. unscript scriptname Delete the script named scriptname. EXIT STATUS The ddb utility exits 0 on success, and >0 if an error occurs. EXAMPLES The following example defines a script that will execute when the kernel debugger is entered as a result of a break signal: ddb script kdb.enter.break="show pcpu; bt" The following example will delete the script: ddb unscript kdb.enter.break For further examples, see the ddb(4) and textdump(4) manual pages. SEE ALSO ddb(4), textdump(4), sysctl(8) HISTORY The ddb utility first appeared in FreeBSD 7.1. AUTHORS Robert N M Watson BUGS Ideally, ddb would not exist, as all pertinent aspects of ddb(4) could be configured directly via sysctl(8). FreeBSD 13.0 December 24, 2008 FreeBSD 13.0
NAME | SYNOPSIS | DESCRIPTION | OUTPUT CAPTURE | SCRIPTING | EXIT STATUS | EXAMPLES | SEE ALSO | HISTORY | AUTHORS | BUGS
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