shadow/man/limits.5

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.TH LIMITS 5
.SH NAME
limits \- Resource limits definition
.SH DESCRIPTION
The
.I limits
file (/etc/limits by default or LIMITS_FILE defined config.h)
describes the resource limits you wish to impose.
It should be owned by root and readable by root account only.
.PP
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).
.PP
Each line describes a limit for a user in the form:
.sp
.I user LIMITS_STRING
.PP
The \fBLIMITS_STRING\fP is a string of a concatenated list of resource limits.
Each limit consists of a letter identifier followed by a numerical limit.
.PP
The valid identifiers are:
.sp
A: max address space (KB)
.br
C: max core file size (KB)
.br
D: max data size (KB)
.br
F: maximum filesize (KB)
.br
M: max locked-in-memory address space (KB)
.br
N: max number of open files
.br
R: max resident set size (KB)
.br
S: max stack size (KB)
.br
T: max CPU time (MIN)
.br
U: max number of processes
.br
L: max number of logins for this user
.br
P: process priority, set by \fBsetpriority\fR(2).
.PP
For example, \fIL2D2048N5\fP is a valid \fBLIMITS_STRING\fP. For reading convenience,
the following entries are equivalent:
.sp
username L2D2048N5
.br
username L2 D2048 N5
.PP
Be aware that after \fIusername\fP the rest of the line is considered a limit
string, thus comments are not allowed. A invalid limits string will be
rejected (not considered) by the login program.
.PP
The default entry is denoted by username "\fB*\fP". If you have multiple \fIdefault\fP
entries in your \fBLIMITS_FILE\fP, then the last one will be used as the default
entry.
.PP
To completely disable limits for a user, a single dash "\fB-\fP" will do.
.PP
Also, please note that all limit settings are set PER LOGIN. They are
not global, nor are they permanent. Perhaps global limits will come, but
for now this will have to do ;)
.SH FILES
/etc/limits
.SH SEE ALSO
.BR login (1),
.BR setpriority (2),
.BR setrlimit (2)
.SH AUTHOR
Cristian Gafton (gafton@sorosis.ro)