GCORE(1) General Commands Manual GCORE(1)

gcore — get core images of running processes

gcore [-s] [-v] [-b size] [-o path | -c pathformat] pid

The gcore program creates a core file image of the process specified by pid. The resulting core file can be used with a debugger, e.g. lldb(1), to examine the state of the process.

The following options are available:

Suspend the process while the core file is captured.
Report progress on the dump as it proceeds.
size
Limit the size of the core file to size MiBytes.

The following options control the name of the core file:

path
Write the core file to path.
pathformat
Write the core file to pathformat. The pathformat string is treated as a pathname that may contain various special characters which cause the interpolation of strings representing specific attributes of the process into the name.

Each special character is introduced by the % character. The format characters and their meanings are:

The name of the program being dumped, as reported by ps(1).
The uid of the process being dumped, converted to a string.
The pid of the process being dumped, converted to a string.
The time when the core file was taken, converted to ISO 8601 format.
Output a percent character.

The default file name used by gcore is %N-%P-%T. By default, the core file will be written to a directory whose name is determined from the kern.corefile MIB. This can be printed or modified using sysctl(8).

The directory where the core file is to be written must be accessible to the owner of the target process.

gcore will not overwrite an existing file, nor will it create missing directories in the path.

/cores/%N-%P-%T
default pathname for the corefile.

The gcore utility exits 0 on success, and >0 if an error occurs.

lldb(1), core(5), Mach-O(5), sudo(8), sysctl(8)

With the -b flag, gcore writes out as much data as it can up to the specified limit, even if that results in an incomplete core image. Such a partial core dump may confuse subsequent programs that attempt to parse the contents of such files.

February 10, 2016 Darwin