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.Because this involves set-user-ID privileges, pcnfsd must be run as root.Every print request from the client includes the name of the printer that is to be used.In Linux, this name corresponds to aprinter definition in the /etc/printcap(5) database.If you want to define a non-standard way of processing print data, youshould define a new printer and arrange for the client to print to this printer.There are two ways of setting up a new printer.The first involves the addition of an entry to /etc/printcap(5) and the creation of filters to perform the required processing.This is outside the scope of this discussion.In addition, pcnfsd includes a mechanism by which you can define virtualprinters known only to pcnfsd clients.Each printer is defined by a line in the /etc/pcnfsd.conf file of the following form:printer name alias-for commandname is the name of the printer you want to define.alias-for is the name of a real printer that corresponds to this printer.For example, a request to display the queue for name is translated into the corresponding request for the printer alias-for.Ifyou have defined a printer in such a way that there is no real printer to which it corresponds, use a single - for this field.(See the definition of the printer test for an example.) command is a command that will be executed whenever a file is printedon name.This command is executed by the shell at /bin/sh using the -c option.For complex operations, you shouldconstruct an executable shell program and invoke that in command.Consider the following sample /etc/pcnfsd.conf file:printer rotated lw /usr/local/bin/enscript -2r $FILEprinter test - /usr/bin/cp $FILE/usr/tmp/$HOST$USERIf a client system prints a job on the printer rotated, the utility enscript is invoked to pre-process the file $FILE.In this case,the -2r option causes the file to be printed in two-column rotated format on the default PostScript printer.If the clientrequests a list of the print queue for the printer rotated, the pcnfsd daemon translates this into a request for a listing for theprinter lw.The printer test is used only for testing.Any file sent to this printer is copied into /usr/tmp.Any request to list the queue,check the status, and so on of printer test is rejected because the alias-for is specified as -. plipconfig1357RECONFIGURATIONpcnfsd detects when printers are added or deleted and rebuilds its list of valid printers.To do this, it checks the modificationtime of /etc/printcap.However, it does not monitor the file /etc/pcnfsd.conf for updates; if you change this file, it is stillnecessary to kill and restart pcnfsd so the changes can take effect.FILE/etc/pcnfsd.confSEE ALSOlpr(1), lprm(1), lpc(8), lpq(1)25 June 1995plipconfigplipconfig Fine-tune PLIP device parameters.SYNOPSISplipconfig interfaceplipconfig interface [nibble NN] [trigger NN] [unit NN]DESCRIPTIONplipconfig is used to improve PLIP performance by changing the default timing parameters used by the PLIP protocol.Results are dependent on the parallel port hardware, cable, and the CPU speed of each machine on each end of the PLIPlink.If the single interface argument is given, plipconfig displays the status of the given interface only.Otherwise, it tries to setthe options.OPTIONSnibble NN Sets the nibble wait value in microseconds.Default is 3000.trigger NN Sets the trigger wait value in microseconds.Default is 500.unit NN Sets the number of units of delay.Default is 1.In some cases, PLIP speed can be improved by lowering the default values.Values that are too low might cause excess use ofCPU, poor interrupt response time resulting in serial ports dropping characters, or in dropping PLIP packets.Changing theplip MTU can also affect PLIP speed.SEE ALSOifconfig(8)BUGSNone so far.AUTHORJohn Paul Morrison (jmorriso@bogomips.ee.ubc.ca, ve7jpm@ve7jpm.ampr.org)1 July 1994 Part VIII: Administration and Privileged Commands1358pingping Send ICMP ECHO_REQUEST packets to network hosts.SYNOPSIS/etc/ping [ -r ][-v ] host [ packetsize ][count ]DESCRIPTIONThe DARPA Internet is a large and complex aggregation of network hardware, connected together by gateways.Tracking asingle-point hardware or software failure can often be difficult.Ping utilizes the ICMP protocol s mandatory ECHO_REQUESTdatagram to elicit an ICMP ECHO_RESPONSE from a host or gateway.ECHO_REQUEST datagrams ( pings ) have an IP and ICMPheader, followed by a struct timeval and then an arbitrary number of pad bytes used to fill out the packet.Defaultdatagram length is 64 bytes, but this may be changed using the command-line option.Other options are-r Bypass the normal routing tables and send directly to a host on an attached network.Ifthe host is not on a directly attached network, an error is returned.This option can beused to ping a local host through an interface that has no route through it (for example,after the interface was dropped by routed(8C)).-v Verbose output.ICMP packets other than ECHO_RESPONSE that are received are listed
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