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man pages section 1: User Commands

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Updated: Wednesday, February 9, 2022



gcore - get core images of running processes


gcore [-pgFR] [-o filename] [-c content] process-id...


The gcore utility creates a core image of each specified process. By default, the name of the core image file for the process whose process ID is process-id is core.process-id.


The following options are supported:

–c content

Produces core image files with the specified content. The content description uses the same tokens as in coreadm(8). The –c option does not apply to cores produced due to the –p or –g flags.


Force. Grabs the target process even if another process has control.


Produces core image files in the global core file repository with the global content as configured by coreadm(8). The command fails if the user does not have permissions to the global core file repository.

–o filename

Substitutes filename in place of core as the first part of the name of the core image files. filename can contain the same tokens to be expanded as the paths in coreadm(8).


Produces a core image file in the process-specific location with the process-specific content for each process as configured by coreadm(8). The command fails if the user does not have permissions to the per-process core file repository.


By default, gcore takes into account any pruning requests that were made using memcntl(2) and are currently active in the process' address space. Specifying this flag while using gcore on such a process would result in any active pruning requests being ignored while dumping the core of the process.


Bring in the content of the process to memory before dumping its core. This is a best effort and pages read are not locked. For large processes, this option is expected to shorten the time they remain stopped, at the cost of increasing the total time of execution of the command.


The following operand is supported:


process ID


Caution should be exercised when using the –F flag. Imposing two controlling processes on one victim process can lead to chaos. Safety is assured only if the primary controlling process, typically a debugger, has stopped the victim process and the primary controlling process is doing nothing at the moment of application of the proc tool in question.

Exit Status

The following exit values are returned:


On success.


On failure, such as non-existent process ID.



core images


See attributes(7) for descriptions of the following attributes:

Interface Stability
See below.

The command syntax is Committed. The Output Formats are Uncommitted.

See Also

kill(1), setrlimit(2), core(5), proc(5), attributes(7), memcntl(2), coreadm(8)


gcore is unaffected by the setrlimit(2) system call using the RLIMIT_CORE value.