getrlimit
resource limit query and management interface
TLDR
Get resource limits (shell)
$ ulimit -a
Get specific limit (open files)copy
$ ulimit -n
Show resource limits of a processcopy
$ prlimit --pid [pid]
Set open file limit for a commandcopy
$ prlimit --nofile=4096 [command]
copy
SYNOPSIS
#include <sys/resource.h>int getrlimit(int resource, struct rlimit \*rlim);int setrlimit(int resource, const struct rlimit \*rlim);
DESCRIPTION
getrlimit() and setrlimit() are system calls for querying and setting resource limits for the calling process. These limits control maximum values for various system resources.The ulimit shell built-in provides command-line access to these limits. Limits have soft (current) and hard (maximum) values.
PARAMETERS
resource
Resource type (RLIMITNOFILE, RLIMITNPROC, etc.).rlim
Pointer to rlimit structure with soft/hard limits.
CONFIGURATION
/etc/security/limits.conf
PAM configuration for setting default resource limits per user or group./etc/systemd/system.conf
Systemd-wide default resource limits for services and user sessions.
SHELL ACCESS
$ ulimit -n # Open files
ulimit -u # Max processes
ulimit -s # Stack size
ulimit -a # All limits
ulimit -n 4096 # Set open files limit
ulimit -u # Max processes
ulimit -s # Stack size
ulimit -a # All limits
ulimit -n 4096 # Set open files limit
copy
CAVEATS
System call, not a command. Non-root users cannot raise hard limits. Some limits affect child processes. PAM may set limits at login.
SEE ALSO
ulimit(1), prlimit(1), limits.conf(5)