How do I set default printer in my Bash shell under CentOS Linux or FreeBSD unix desktop operating systems?

CUPS is default printing system for Unix and Linux systems. It provides many ways to set the default printer destination. The “LPDEST” and “PRINTER” environment variables are consulted first for the default printer.

Syntax

The syntax is as follows:

export PRINTER=printer-Name-Here

Linux / Unix: Bash Set Default Printer

Open a terminal and edit ~/.bashrc file, enter:
$ vi ~/.bashrc
Set default printer to sales_hplj_1536:

export PRINTER=sales_hplj_1536

OR

PRINTER=sales_hplj_1536
export PRINTER

Save and close the file. Relogin into your account and print a test page using lp* commands such as lp, lpr, lpq, and lprm.
$ cat testfile.txt | lp
OR print ls command man page:
$ zcat /usr/share/man/man1/ls.1.gz | groff -man -Tps | lpr

Linux / Unix: CSH / TCSH Set Default Printer

Edit ~/.cshrc, enter:
$ vi ~/.cshrc
Set default printer to lab_hp8500:

setenv PRINTER lab_hp8500

Save and close the file. Relogin your account and print a test page using standard Unix lp* commands.