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Top Forums Shell Programming and Scripting WHy the double square brackets? Post 302265713 by methyl on Monday 8th of December 2008 09:33:56 AM
Old 12-08-2008
#!/bin/ksh
if [ ! -s valid_users.tmp -a ! -s invalid_users.tmp ]
then
exit
fi
 

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VDETAPLIB(1)						      General Commands Manual						      VDETAPLIB(1)

NAME
vdetaplib - Virtual Distributed Ethernet tap emulation library SYNOPSIS
No synopsis DESCRIPTION
vdetaplib is a library that emulates tap (tuntap level2 interface, see in kernel sources Documentation/networking/tun.c) and connects tap virtual interfaces to vde networks. To use it, the libvdetab.so library must be preloaded (sh, ksh or bash syntax): export LD_PRELOAD=/usr/lib/vde2/libvdetap.so (csh, tchs syntax): setenv LD_PRELOAD /usr/lib/vde2/libvdetap.so If you want to divert all tap requests to a single vde_switch set the variable VDEALLTAP to the vde socket. (sh, ksh or bash syntax): export VDEALLTAP=/tmp/vde.ctl (csh, tchs syntax): setenv VDEALLTAP /tmp/vde.ctl It is possible to set each single interface to different vde_switches by setting the environment variable with the same name of the inter- face. (sh, ksh or bash syntax): export tap0=/tmp/vde.ctl export tap1=/tmp/myvde.ctl export ppc=/tmp/ppc.ctl (csh, tchs syntax): setenv tap0 /tmp/vde.ctl setenv tap1 /tmp/myvde.ctl setenv ppc /tmp/ppc.ctl It is also possible to specify port, group or mode for a given interface setting environment variables as in the following example. (sh, ksh or bash syntax): export tap0_port=5 export tap0_group=vde-net export tap0_mode=0660 (csh, tchs, syntax): setenv tap0_port 5 setenv tap0_group vde-net setenv tap0_mode 0660 The variable to set the specific interface is checked first then VDEALLTAP. VDEALLTAP thus works as a default choice for the vde switch to be used. If VDEALLTAP is not set and there is no specific environment variable (and for tun -- IFF_TUN interfaces) the kernel provided interface is used. In this latter case access to /dev/net/tun is required, generally root access. NOTICE
Virtual Distributed Ethernet is not related in any way with www.vde.com ("Verband der Elektrotechnik, Elektronik und Informationstechnik" i.e. the German "Association for Electrical, Electronic & Information Technologies"). SEE ALSO
vde_switch(1), vdeq(1). AUTHOR
VDE is a project by Renzo Davoli <renzo@cs.unibo.it> Virtual Distributed Ethernet December 6, 2006 VDETAPLIB(1)
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