I got confused between many print command. On my system, i see lp, lpr, lpr.cups, after i install driver for my samsung printer, i have another one: llpr! Which one is the real executable file that prepare the print job and send to the printer?
Hope to have some explaination from experts
Thai

you could see their manpages for differences "man lp", "man lpr" etc. etc..

I did but i couldnt see the differences!!!
BTW, is there anyway to make all application especially firefox, gedit, openOffice use the print interface provided by the printer manufature (samsung)? The print interface is installed in /usr/local/linuxprinter/bin/llpr (this is the binary file).

Some apps like xpdf allow you to specify your own printer command, but I'm not sure about firefox, openoffice etc

*edit: type about:config in firefox address bar and search for print. You will see a setting for print.command that uses lpr

One difference between lp and lpr is that you can specify options for lp that are saved and can be read back with lpoptions:

$ lpoptions media=A4
$ lpoptions
$ job-sheets=none,none media=A4 outputorder=reverse orientation-requested=3 portrait=true PageSize=A4

I'm not sure you can do the same with lpr, or if lpr also reads these settings

I change the pint.command in firefox but it does not lauch the print interface but sending the document to the application interface directly thus, the result is nothing is printed out

On my CentOS server, the printing commands seem to be symlinks to alternative print servers in /etc/alternative/print*. I would assume that whichever command you choose will work because it is linked to the default print server. So if you are using cups, lp would point to lp.cups and lp to lp.cups etc.