LSHELL(1)

NAME
lshell - Securely establish process limits upon login

SYNOPSIS
Make a copy a user's login shell.

DESCRIPTION
LShell allows a system administrator to easily set and maintain per-user limits on CPU time, number of processes, virtual memory usage, and open files. A master file (/etc/limits) contains a default entry and overriding entries for specific users.

Copy the real shell into /bin/shells and replace the shell in /bin with a copy of lshell.

Repeat this for every legal login shell on your system.

/etc/lshell.conf
This file contains the entries for the resource limits. Each line consists of a username optionally followed by resource limits. If resource limits are present, they may be followed by a comment.

The last line is the default entry and can contain any name that does not represent a user on the system. Default is typically used.

If there is no second field, no limits are imposed on that user. Otherwise, the second field consists of a letter identifying the resource to be limited and a number specifying the limit. Multiple limits are simply concatenated together. If multiple entries appear for the same user, the first is used.

Valid resource limiters are F followed by the number of file descriptors, P followed by the number of processes, C followed by the maximum CPU time in minutes, and D followed by the in-memory data limit in Megabytes.

Reasonable limits for typical users are C60D20F96P28

VERSION
lshell version 2.01, March 11, 1995.

WARNINGS
The user name in /etc/lshell.conf must exactly match (case included) the entry in /etc/lshell.conf.

BUGS
None. Just undocumented features. If you discover any bugs, please mail them to the author (Joel Katz) at Stimpson@Panix.COM.

If all shells do not live in /bin LShell will work properly.

Some versions of bash fail to correctly report the limit on the number of file descriptors, however lshell does set this limit properly.