ulimit

Linux · System · reference only

What it does

Shows and sets the resource limits of the current shell and the processes it launches, such as open files or processes.

Syntax

ulimit [opciones] [límite]

Options and parameters

• -a

  Shows all current limits.

• -n

  Maximum number of open files.

• -u

  Maximum number of processes for the user.

• -c

  Maximum size of core dumps.

• -s

  Maximum stack size.

• -t

  Maximum CPU time, in seconds.

• -H

  Acts on the hard limit, which cannot be exceeded.

• -S

  Acts on the soft limit, the one applied by default.

Usage examples

• ulimit -a

  Shows all the shell's limits.

• ulimit -n

  Shows how many files a process can open.

• ulimit -n 4096

  Raises the open file limit for this session.

• ulimit -Hn

  Shows the hard limit of open files.

Notes and common mistakes

• It only affects the current shell and its child processes.
• For permanent limits, configure /etc/security/limits.conf.

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• apt-cache
• cal
• date
• df
• dpkg-deb
• dpkg-query