PG(1) User Commands PG(1)

NAME

pg - files perusal filter for CRTs

SYNOPSIS

pg [-number] [-p string] [-cefnrs] [+ linenumber]
[+/ pattern /] [filename]...

DESCRIPTION

The pg command is a filter that allows the examination of filenames
one screenful at a time on a CRT. If the user types a RETURN, another
page is displayed; other possibilities are listed below.


This command is different from previous paginators in that it allows
you to back up and review something that has already passed. The
method for doing this is explained below.


To determine terminal attributes, pg scans the terminfo(5) data base
for the terminal type specified by the environment variable TERM. If
TERM is not defined, the terminal type dumb is assumed.

OPTIONS

-number
An integer specifying the size (in lines) of the
window that pg is to use instead of the default. (On a
terminal containing 24 lines, the default window size
is 23).


-pstring
pg uses string as the prompt. If the prompt string
contains a %d, the first occurrence of %d in the
prompt will be replaced by the current page number
when the prompt is issued. The default prompt string
is ``:''.


-c
Home the cursor and clear the screen before displaying
each page. This option is ignored if clear_screen is
not defined for this terminal type in the terminfo(5)
data base.


-e
pg does not pause at the end of each file.


-f
Normally, pg splits lines longer than the screen
width, but some sequences of characters in the text
being displayed (for instance, escape sequences for
underlining) generate undesirable results. The -f
option inhibits pg from splitting lines.


-n
Normally, commands must be terminated by a <newline>
character. This option causes an automatic end of
command as soon as a command letter is entered.


-r
Restricted mode. The shell escape is disallowed. pg
prints an error message but does not exit.


-s
pg prints all messages and prompts in the standard
output mode (usually inverse video).


+linenumber
Start up at linenumber.


+/pattern/
Start up at the first line containing the regular
expression pattern.

OPERANDS

The following operands are supported:

filename
A path name of a text file to be displayed. If no
filename is given, or if it is -, the standard input is
read.

USAGE

Commands

The responses that may be typed when pg pauses can be divided into
three categories: those causing further perusal, those that search,
and those that modify the perusal environment.


Commands that cause further perusal normally take a preceding
address, an optionally signed number indicating the point from which
further text should be displayed. This address is interpreted in
either pages or lines depending on the command. A signed address
specifies a point relative to the current page or line, and an
unsigned address specifies an address relative to the beginning of
the file. Each command has a default address that is used if none is
provided.


The perusal commands and their defaults are as follows:

(+1)<newline> or <blank>
This causes one page to be displayed. The
address is specified in pages.


(+1) l
With a relative address this causes pg to
simulate scrolling the screen, forward or
backward, the number of lines specified.
With an absolute address this command
prints a screenful beginning at the
specified line.


(+1) d or ^D
Simulates scrolling half a screen forward
or backward.


if
Skip i screens of text.


iz
Same as <newline> except that i, if
present, becomes the new default number
of lines per screenful.


The following perusal commands take no address.

. or ^L
Typing a single period causes the current page of text
to be redisplayed.


$
Displays the last full window in the file. Use with
caution when the input is a pipe.


The following commands are available for searching for text patterns
in the text. The regular expressions are described on the regex(7)
manual page. They must always be terminated by a <newline>, even if
the -n option is specified.

i/pattern/
Search forward for the ith (default i=1) occurrence of
pattern. Searching begins immediately after the current
page and continues to the end of the current file,
without wrap-around.


i^pattern^


i?pattern?
Search backwards for the ith (default i=1) occurrence
of pattern. Searching begins immediately before the
current page and continues to the beginning of the
current file, without wrap-around. The ^ notation is
useful for Adds 100 terminals which will not properly
handle the ?.


After searching, pg will normally display the line found at the top
of the screen. This can be modified by appending m or b to the search
command to leave the line found in the middle or at the bottom of the
window from now on. The suffix t can be used to restore the original
situation.


The user of pg can modify the environment of perusal with the
following commands:

in
Begin perusing the ith next file in the command line.
The i is an unsigned number, default value is 1.


ip
Begin perusing the ith previous file in the command
line. i is an unsigned number, default is 1.


iw
Display another window of text. If i is present, set
the window size to i.


s filename
Save the input in the named file. Only the current file
being perused is saved. The white space between the s
and filename is optional. This command must always be
terminated by a <newline>, even if the -n option is
specified.


h
Help by displaying an abbreviated summary of available
commands.


q or Q
Quit pg.


!command
Command is passed to the shell, whose name is taken
from the SHELL environment variable. If this is not
available, the default shell is used. This command must
always be terminated by a <newline>, even if the -n
option is specified.


At any time when output is being sent to the terminal, the user can
hit the quit key (normally CTRL-\) or the interrupt (break) key. This
causes pg to stop sending output, and display the prompt. The user
may then enter one of the above commands in the normal manner.
Unfortunately, some output is lost when this is done, because any
characters waiting in the terminal's output queue are flushed when
the quit signal occurs.


If the standard output is not a terminal, then pg acts just like
cat(1), except that a header is printed before each file (if there is
more than one).

Large File Behavior

See largefile(7) for the description of the behavior of pg when
encountering files greater than or equal to 2 Gbyte ( 2^31 bytes).

EXAMPLES

Example 1: An example of the pg command.

The following command line uses pg to read the system news:


example% news | pg -p "(Page %d):"

ENVIRONMENT VARIABLES

See environ(7) for descriptions of the following environment
variables that affect the execution of pg: LC_CTYPE, LC_MESSAGES, and
NLSPATH.


The following environment variables affect the execution of pg:

COLUMNS
Determine the horizontal screen size. If unset or NULL,
use the value of TERM, the window size, baud rate, or some
combination of these, to indicate the terminal type for
the screen size calculation.


LINES
Determine the number of lines to be displayed on the
screen. If unset or NULL, use the value of TERM, the
window size, baud rate, or some combination of these, to
indicate the terminal type for the screen size
calculation.


SHELL
Determine the name of the command interpreter executed for
a !command.


TERM
Determine terminal attributes. Optionally attempt to
search a system-dependent database, keyed on the value of
the TERM environment variable. If no information is
available, a terminal incapable of cursor-addressable
movement is assumed.

EXIT STATUS

The following exit values are returned:

0
Successful completion.


>0
An error occurred.

FILES

/tmp/pg*

temporary file when input is from a pipe


/usr/share/lib/terminfo/?/*

terminal information database

SEE ALSO

cat(1), grep(1), more(1), terminfo(5), attributes(7), environ(7),
largefile(7), regex(7)

NOTES

While waiting for terminal input, pg responds to BREAK, CTRL-C, and
CTRL-\ by terminating execution. Between prompts, however, these
signals interrupt pg's current task and place the user in prompt
mode. These should be used with caution when input is being read from
a pipe, since an interrupt is likely to terminate the other commands
in the pipeline.


The terminal /, ^, or ? may be omitted from the searching commands.


If terminal tabs are not set every eight positions, undesirable
results may occur.


When using pg as a filter with another command that changes the
terminal I/O options, terminal settings may not be restored
correctly.

February 25, 1996 PG(1)