prlimit

prlimit is a command-line utility used to view and adjust the resource limits (rlimits) of a process on Linux and other Unix-like systems. It interacts with the kernel via the getrlimit and setrlimit interfaces, allowing administrators and developers to bound or inspect a process’s resource usage.

Overview and purpose

prlimit provides a convenient way to query the soft and hard limits for various resources, such as CPU time, file sizes, data segment size, stack size, memory, and the number of open files. It can operate on a specific process identified by PID or on the current process when no PID is given. If no specific resources are requested, prlimit can display all limits for the target process.

Usage and options

Typical usage is prlimit [OPTIONS] [PID]. Common options include:

- -a, --all: display all resource limits for the target process

- -p, --pid PID: select a specific process by PID (default is the current process)

Resource specification

Limits are provided as resource=value pairs. Values can be a single number (applied to both soft and hard limits) or a soft:hard pair to set distinct soft and hard limits. Resource names usually correspond to RLIMIT constants, such as cpu, fsize, data, stack, core, nofile (open files), and others supported by the system.

Examples

- prlimit --pid 123 --nofile=1024:2048 sets the soft and hard limits for open files on process 123.

- prlimit -a displays all limits for the current process.

- prlimit --cpu=60 resets the CPU time limit for the current process.

Notes

Raising hard limits typically requires appropriate privileges; lowering limits is generally allowed for regular users within policy. Some limits may be constrained by system-wide settings or user quotas.

See also

getrlimit, setrlimit, RLIMIT.