PG(1) INTERACTIVE UNIX System PG(1)
NAME
pg - file perusal filter for CRTs
SYNOPSIS
pg [ - number] [-p string] [-cefns] [ + linenumber]
[ +/ pattern / ] [files ...]
DESCRIPTION
The pg command is a filter which allows the examination of
files one screenful at a time on a CRT. (The file name -
and/or NULL arguments indicate that pg should read from the
standard input.) Each screenful is followed by a prompt.
If the user types a carriage return, another page is
displayed; other possibilities are enumerated 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.
In order to determine terminal attributes, pg scans the ter-
minfo(4) data base for the terminal type specified by the
environment variable TERM. If TERM is not defined, the ter-
minal type dumb is assumed.
The command line options are:
-number
An integer specifying the size (in lines) of the window
that pg is to use instead of the default. (On a termi-
nal containing 24 lines, the default window size is
23).
-p string
Causes pg to use 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(4)
data base.
-e Causes pg not to 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 (e.g., escape sequences for underlining) gen-
erate undesirable results. The -f option inhibits pg
from splitting lines.
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-n Normally, commands must be terminated by a <newline>
character. This option causes an automatic end of com-
mand as soon as a command letter is entered.
-s Causes pg to print all messages and prompts in standout
mode (usually inverse video).
+linenumber
Start up at linenumber.
+/pattern/
Start up at the first line containing the regular
expression pattern.
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 which cause further perusal normally take a preced-
ing 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 com-
mand 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.
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 windowful in the file. Use with cau-
tion when the input is a pipe.
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The following commands are available for searching for text
patterns in the text. The regular expressions described in
ed(1) are available. 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 suf-
fix 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
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PG(1) INTERACTIVE UNIX System PG(1)
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 control-\) or the inter-
rupt (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, due to the fact that 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).
EXAMPLE
A sample usage of pg in reading system news would be
news | pg -p "(Page %d):"
NOTES
While waiting for terminal input, pg responds to BREAK, DEL,
and ^ 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.
Users of Berkeley's more will find that the z and f commands
are available, and that the terminal /, ^, or ? may be omit-
ted from the searching commands.
FILES
/usr/lib/terminfo/?/* terminal information database
/tmp/pg* temporary file when input is from a
pipe
SEE ALSO
ed(1), grep(1).
terminfo(4) in the INTERACTIVE SDS Guide and Programmer's
Reference Manual.
BUGS
If terminal tabs are not set every eight positions, undesir-
able 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.
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