Files
Overview
The UNIX directory
hierarchy
Filesystems
Manipulating files
Creating
directories
Creating files
links
'Dot' files
Protecting files
Groups
File access
control
Changing
privileges
File
contents
Text files
Comparing
files
Filtering
files
Non-text files
Printing
files
File archives and file
compression
Other relevant commands
Summary
Exercises
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Printing files
Although you will probably spend a lot of time sitting in front
of a computer terminal, you will from time to time need to get
'hard copy' of documents; that is, you will need to print them onto
paper. To do this, type lp ('lineprinter') followed by
the name of the file or files you wish to be printed. If you omit
filenames, the standard input will be printed, so that can have
data piped into it. On Linux systems lpr is used
instead of lp. It is important that you only attempt
to print text files. Most modern printers will be sensible if you
send them unprintable files, and simply refuse to print them, but a
few will go haywire.
Your machine will be set up with a 'default' printer, and your
system administrator should have told you which this is and where
it is located. If you give to lp the option
-d ('destination') followed by the name of another
printer, that printer will be used instead. The option
-n ('numerical') followed by a number will cause that
number of copies of the document to be printed (use with care!).
For instance, to print 2 copies of file myfile on the
printer named def:
$ lp -n 2 -d def myfile
It is a fact of life that documents stored on a machine are
changed frequently. When a file is sent to a printer, it is often
useful for an indication to be given as to when the file was
printed (so the reader will be reminded how out-of-date it may be).
It is also useful, when the document is long, for each page to be
printed together with a header containing useful information such
as the page number. When a file is printed with lp,
that file is printed completely naked; nothing except the
characters in the file appear on paper. The command pr
is designed to remedy this situation; it has numerous options,
which allow you to tailor your files to particular printers.
pr divides the input into pages, each
commencing with a header naming the file and the date and time, and
ending with a trailer of blank lines. The size (number of columns
and width) of each page and the size of the header and trailer can
be changed, output can be multi-column, and various other
attributes of the output can be altered. The output of
pr is sent to standard output, and so must be piped to
lp. For example, the following command will print file
abc on the printer named def, 2 columns
per page (option -2, 50 lines per page (using option
-l):
$ pr -2 -l 50 abc | lp -d
def
To use pr effectively, you must know the
characteristics of the printer (or printers) to which you have
access; your system administrator should provide you with that
information.
It is common nowadays for laser printers to be available. Rather
than having a fixed set of characters like a line printer, or a
coarse selection of symbols that can be created by an artistic user
such as in a dot-matrix printer, a laser printer is suitable for
intricate graphical printing. In order to use such facilities,
files for a laser printer must be in a special code, such as
PostScript, which most printers use for formatting documents. It is
worth mentioning that most laser printers will accept text input
just like other printers.
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