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limits(5) - limits - Resource limits definition - man 5 limits

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LIMITS(5)                                                            LIMITS(5)

       limits - Resource limits definition

       The  limits  file(1,n)  (/etc/limits  by default or LIMITS_FILE defined con-
       fig.h) describes the resource limits you wish to impose. It  should  be
       owned by root and readable by root account only.

       By default no quotas are imposed on 'root'. In fact, there is no way to
       impose limits via this procedure to root-equiv accounts (accounts  with
       UID 0).

       Each line describes a limit for a user in(1,8) the form:

       user LIMITS_STRING

       The  LIMITS_STRING  is a string(3,n) of a concatenated list of resource lim-
       its.  Each limit consists of a letter identifier followed by a  numeri-
       cal limit.

       The valid identifiers are:

       A: max address space (KB)
       C: max core file(1,n) size (KB)
       D: max data size (KB)
       F: maximum filesize (KB)
       M: max locked-in-memory address space (KB)
       N: max number of open(2,3,n) files
       R: max resident set(7,n,1 builtins) size (KB)
       S: max stack size (KB)
       T: max CPU time(1,2,n) (MIN)
       U: max number of processes
       K: file(1,n) creation mask, set(7,n,1 builtins) by umask(2).
       L: max number of logins for this user
       P: process priority, set(7,n,1 builtins) by setpriority(2).

       For  example,  L2D2048N5  is  a valid LIMITS_STRING. For reading conve-
       nience, the following entries are equivalent:

       username L2D2048N5
       username L2 D2048 N5

       Be aware that after username the rest of the line is considered a limit
       string(3,n),  thus comments are not allowed. A invalid limits string(3,n) will be
       rejected (not considered) by the login(1,3,5) program.

       The default entry is denoted by username  "*".  If  you  have  multiple
       default  entries in(1,8) your LIMITS_FILE, then the last one will be used as
       the default entry.

       To completely disable limits for a user, a single dash "-" will do.

       Also, please note that all limit settings are set(7,n,1 builtins) PER LOGIN.  They  are
       not  global,  nor  are they permanent. Perhaps global limits will come,
       but for now this will have to do ;)


       login(1,3,5)(1), setpriority(2), setrlimit(2)

       Cristian Gafton (


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