LPI Linux Certification in a Nutshell (57 page)

lp

lp  [  -E ] [ -U
username
] [ -c ] [ -d
destination
[/
instance
] ]
[ -h
hostname
[:
port
] ] [ -m ]
[ -n
num-copies
] [ -o
option
[=
value
] ] [ -q
priority
] [ -s ] [ -t
title
]
[ -H
handling
]  [  -P
page-list
] [ -- ] [
file(s)
]

lp
submits files for printing
or alters a pending job.

Print a double-sided legal document to a printer called
“foo”:

$
lp -d foo -o media=legal -o sides=two-sided-long-edge filename

Print an image across four pages:

$
lp -d bar -o scaling=200 filename

Print a text file with 12 characters per inch, 8 lines per
inch, and a 1-inch left margin:

lp -d bar -o cpi=12 -o lpi=8 -o page-left=72 filename

cancel

cancel [ -E ] [ -U
username
] [ -a ] [ -h
hostname
[:
port
] ] [ -u
username
] [
id
]
[
destination
] [
destination-id
]

cancel
removes the specified
print jobs from the queue.

lpstat

lpstat [ -E ] [ -U
username
] [ -h
hostname
[:
port
] ] [ -l ] [ -W
which-jobs
]
[ -a [
destination(s)
] ] [ -c [
class(es)
] ] [ -d ]
[ -o [
destination(s)
] ]
[ -p [
printer(s)
] ] [ -r ] [ -R ] [ -s ] [ -t ] [ -u [
user(s)
] ]
[ -v [
printer(s)
] ]

lpstat
displays status
information about the current classes, jobs, and printers. When
run with no arguments, it lists jobs queued by the current
user.

lpadmin

lpadmin [ -E ] [-U
username
] [ -h
server
[:
port
] ] -d
destination
lpadmin [ -E ] [-U
username
] [ -h
server
[:
port
] ] -p
printer option(s)
lpadmin [ -E ] [-U
username
] [ -h
server
[:
port
] ] -x
destination

lpadmin
configures printer and
class queues provided by CUPS. It can also be used to set the
server default printer or class.

lpq

lpq [
options
] [
users
] [
job#s
]

Query a print queue. If numeric
job#s
are included, only those jobs are
listed. If
users
are listed, only jobs
submitted by those users are listed.

Examine active jobs:

$
lpq
lp is ready and printing
Rank   Owner      Job  Files                 Total Size
active root       193  filter                9443 bytes
1st    root       194  resume.txt            11024 bytes
2nd    root       196  (standard input)      18998 bytes

Here,
filter
is currently being
printed.
resume.txt
is up next, followed by
the 18,998 bytes of data piped into
lpr
’s
standard input.

Examine those same jobs using the long format:

$
lpq -l
lp is ready and printing
root: active                             [job 193AsJRzIt]
filter                           9443 bytes
root: 1st                                [job 194AMj9lo9]
resume.txt                       11024 bytes
root: 2nd                                [job 196A6rUGu5]
(standard input)                 18998 bytes

Examine queue
lp
, which
turns out to be empty:

$
lpq -Plp
no entries

Examine jobs owned by
bsmith
:

$
lpq bsmith
Rank   Owner      Job  Files                 Total Size
7th    bsmith     202  .bash_history         1263 bytes
9th    bsmith     204  .bash_profile         5676 bytes

Using the job numbers reported by
lpq
,
any user may remove her own print jobs from the queue, or the
superuser may remove any job.

lprm

lprm [
-Pname
] [
users
] [
job#s
]
lprm -ly

Remove jobs from a print queue. In the first form,
remove jobs from queue
name
or from the
default queue if
-P
is omitted. If
users
or
jobs
are specified, only those jobs
will be removed. In the second form, all of a normal user’s jobs
will be omitted; for the superuser, the queue will be
emptied.

As a normal user, remove all of your print jobs:

$
lprm -

As the superuser, remove all jobs from queue
ps
:

#
lprm -Pps -

You may occasionally be surprised to see a
no entries
response from
lpq
, despite observing that the printer
is dutifully printing a document. In such cases, the spool has
probably been emptied into the printer’s buffer memory, and the
result is that the job is no longer under the control of the
printing system. To kill such jobs, you need to use the printer’s
controls to stop and delete the job from memory.

lpr

lpr [
options
] [
files
]

Send
files
or standard
input to a print queue. A copy of the input source is placed in
the spool directory under
/var/spool/lpr
until the print job is complete.

Print the file
/etc/fstab
on the
default print queue:

#
lpr /etc/fstab

Print a manpage by piping to
lpr
’s
standard input:

#
man -t 5 printcap | lpr

Disable a print queue:

#
lpc disable lp

Then, attempt to print three copies of a file to the
disabled queue as superuser:

#
lpr -#3 /etc/fstab

This succeeds, despite the disabled printer queue. Now try
as a regular user:

$
lpr -#3 ~/resume.txt
lpr: Printer queue is disabled

As expected, normal users can’t print to the disabled
queue.

Recent errors and related information can be found in
/var/log/cups/error_log
. This file
lists messages from the scheduler, which includes both errors and
warnings. You can view detailed and real-time information about data
transferring, filtering, etc. Sample messages generated by one typical
job are:

I [16/Nov/2009:11:19:07 +0100] [Job 102] Adding start banner page "none".
I [16/Nov/2009:11:19:07 +0100] [Job 102] Adding end banner page "none".
I [16/Nov/2009:11:19:07 +0100] [Job 102] File of type application/postscript
queued by "brunop".
I [16/Nov/2009:11:19:07 +0100] [Job 102] Queued on "PDF" by "brunop".
I [16/Nov/2009:11:19:07 +0100] [Job 102] Started filter
/usr/libexec/cups/filter/pstops (PID 18223)
I [16/Nov/2009:11:19:07 +0100] [Job 102] Started backend
/usr/libexec/cups/backend/cups-pdf (PID 18224)
I [16/Nov/2009:11:19:07 +0100] [Job 102] Completed successfully.
I [16/Nov/2009:11:20:17 +0100] [Job ???] Request file type is
application/postscript.
I [16/Nov/2009:11:20:17 +0100] [Job 103] Adding start banner page "none".
I [16/Nov/2009:11:20:17 +0100] [Job 103] Adding end banner page "none".
I [16/Nov/2009:11:20:17 +0100] [Job 103] File of type application/postscript
queued by "brunop".
I [16/Nov/2009:11:20:17 +0100] [Job 103] Queued on "PDF" by "brunop".
I [16/Nov/2009:11:20:17 +0100] [Job 103] Started filter
/usr/libexec/cups/filter/pstops (PID 18340)
I [16/Nov/2009:11:20:17 +0100] [Job 103] Started backend
/usr/libexec/cups/backend/cups-pdf (PID 18341)
I [16/Nov/2009:11:20:17 +0100] [Job 103] Completed successfully.

The
I
that starts each line
stands for “information.” In this case, no errors or warnings were
generated.

This logfile can be found in
/var/log/cups/page_log
. It keeps information
from each page sent to a printer. Each line contains the following
information (when
applicable
):

printer user job-id date-time page-number num-copies job-billing \
job-originating-host-name
jobname media sides

A sample excerpt follows:

Photosmart_C4500 brunop 86 [31/Oct/2009:12:48:36 +0100] 1 1 - localhost
Photosmart_C4500 brunop 86 [31/Oct/2009:12:48:52 +0100] 2 1 - localhost
adamp23 brunop 87 [02/Nov/2009:13:40:33 +0100] 1 1 - localhost
adamp23 brunop 87 [02/Nov/2009:13:40:33 +0100] 2 1 - localhost
adamp23 brunop 88 [09/Nov/2009:09:31:11 +0100] 1 1 – localhost
PDF root 100 [16/Nov/2009:11:11:52 +0100] 1 1 - localhost
PDF brunop 101 [16/Nov/2009:11:16:38 +0100] 1 1 - localhost

This file can be found in
/var/log/cups/access_log
. It lists each HTTP
resource accessed by a web browser or client. Each line is in an
extended version of the so-called “Common Log Format” used by many web
servers and web reporting tools. A sample follows (lines broken to fit
the page of this book):

localhost - - [16/Nov/2009:17:28:29 +0100] "POST / HTTP/1.1" 200 138 \
CUPS-Get-Default successful-ok
localhost - - [16/Nov/2009:17:28:29 +0100] "POST / HTTP/1.1" 200 552 \
CUPS-Get-Printers successful-ok
localhost - root [16/Nov/2009:17:28:29 +0100] "GET /printers HTTP/1.1" \
200 11258 - -
localhost - root [16/Nov/2009:17:28:29 +0100] "GET \
/images/button-search.gif HTTP/1.1" 200 332 - -
localhost - root [16/Nov/2009:17:28:29 +0100] "GET \
/images/button-clear.gif HTTP/1.1" 200 279 - -

The
cups-config
utility has several
parameters that can be handy while troubleshooting. The options are
described in
Table 18-2
.