pg(1) pg(1)
NAME
pg - file perusal filter for CRTs
SYNOPSIS
pg [-number] [-p string] [-cefnrs] [+linenumber] [+/pattern/] [file . . .]
DESCRIPTION
The pg command is a filter that allows the examination of
files one screenful at a time on a CRT. (If no file is
specified or if it encounters the file name -, pg reads from
standard input.) Each screenful is followed by a prompt. If
the user types a carriage return, another page is displayed;
other possibilities are listed below. pg processes
supplementary code set characters in files, and recognizes
supplementary code set characters in the string given to the
-p option (see below) according to the locale specified in the
LC_CTYPE environment variable [see LANG on environ(5)]. In
regular expressions, pattern searches are performed on
characters, not bytes, as described on ed(1).
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 data
base for the terminal type specified by the environment
variable TERM. If TERM is not defined, the terminal 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
terminal containing 24 lines, the default window size is
23).
-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 data
base.
-e Causes pg not to pause at the end of each file.
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pg(1) pg(1)
-f Normally, pg splits lines longer than the screen width
at characters, but some sequences of characters in the
text being displayed (for example, 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.
-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
``:''. string may contain supplementary code set
characters.
-r Restricted mode. The shell escape is disallowed. pg
will print an error message but does not exit.
-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 basic regular
expression (BRE) patterm [see grep(1)].
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.
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pg(1) pg(1)
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 windowful 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 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
the BRE 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
the BRE pattern. Searching begins immediately before
the current page and continues to the beginning of the
current file, without wrap-around. The ^ notation is
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pg(1) pg(1)
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 press 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
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pg(1) pg(1)
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 except that a header is printed before each file (if
there is more than one).
Files
/usr/share/lib/terminfo/?/*
terminal information database
/tmp/pg*
temporary file when input is from a pipe
/usr/lib/locale/locale/LC_MESSAGES/uxcore.abi
language-specific message file [See LANG on environ(5).]
EXAMPLES
The following command line uses pg to read the system news:
news | pg -p "(Page %d):"
REFERENCES
ed(1), grep(1), more(1), terminfo(4)
NOTICES
While waiting for terminal input, pg responds to BREAK, DEL,
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.
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