pg(1)pg(1)Namepg - file perusal filter for soft-copy terminals
Syntaxpg [-number] [-p string] [-cefs] [+linenumber] [+/pattern/] [files...]
Description
The command is a filter that allows the examination of files one
screenful at a time on a soft-copy terminal. When the file name is
designated by a minus (-) and/or NULL argument, the command reads from
the standard input. Each screenful is followed by a prompt. If the
user types a carriage return, another page is displayed.
This command is different from previous paginators because it allows
you to back up and review material that has already passed.
In order to determine terminal attributes, scans the data base for the
terminal type specified by the environment variable TERM. If TERM is
not defined, the terminal is assumed to be a dumb terminal. The com‐
mand takes responses that can be divided into three categories: those
causing further perusal, those that search, and those that modify the
perusal environment.
Commands causing further perusal normally take a preceding address,
which is 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 spec‐
ifies 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>
Causes one page to be displayed. The address is
specified in pages.
(+1) l Causes to simulate scrolling the screen, forward or
backward, the number of lines specified when used
with a relative address. 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 back‐
ward.
The following perusal commands take no address:
. or ^L Causes the current page of text to be redisplayed.
$ Displays the last window full 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 are available. They
must always be terminated by a <newline>, even if the -n option is
specified.
i/pattern/ Searches forward for the ith (default i=1) occur‐
rence 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?
Searches backwards for the ith (default i=1) occurrence of pat‐
tern. Searching begins immediately before the current page and
continues to the beginning of the current file, without wrap-
around. The circumflex (^) notation is useful for Adds 100 ter‐
minals which do not handle the question mark (?) properly.
After searching, normally displays 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 situa‐
tion.
The user of can modify the environment of perusal with the following
commands:
in Begins perusing the ith next file in the command
line. The i is an unsigned number. Default value
is 1.
i Begins perusing the ith previous file in the com‐
mand line. i is an unsigned number. Default is 1.
iw Displays another window of text. If i is present,
sets the window size to i.
s filename Saves the input in the named file. Only the cur‐
rent file being perused is saved. The white space
between the s and filename is optional. This com‐
mand must always be terminated by a <newline>, even
if the -n option is specified.
h Helps by displaying an abbreviated summary of
available commands.
q or Q Quits
!command The 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 control-\) or the interrupt (break) key. This
causes to stop sending output and to display the prompt. The user may
then enter one of the above commands in the normal manner. Unfortu‐
nately, 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 acts just like except
that a header is printed before each file (if there is more than one).
Options
The command line options are:
-number Specifies the size (in lines) of the window that is to
use instead of the default. (On a terminal containing
24 lines, the default window size is 23).
-p string Causes to use as the prompt. If the prompt string con‐
tains a %d, the first occurrence of %d in the prompt is
replaced by the current page number when the prompt is
issued. The default prompt string is designated by a
colon (:).
-c Homes the cursor and clears the screen before displaying
each page. This option is ignored if clear_screen is
not defined for this terminal type in the data base.
-e Causes not to pause at the end of each file.
-f Inhibits from splitting lines. Normally, splits lines
longer than the screen width, but some sequences of
characters in the text being displayed (for example,
escape sequences for underlining) generate undesirable
results. The -f option prevents the splitting of these
sequences.
-s Causes to print all messages and prompts in standout
mode (usually inverse video).
+linenumber Starts up at linenumber.
+/pattern/ Starts up at the first line containing the regular
expression pattern.
Examples
The following example shows how the command is used reading system
news:
news | pg-p "(Page %d):"
Notes
While waiting for terminal input, responds to BREAK, DEL and the cir‐
cumflex (^) by terminating execution. Between prompts, however, these
signals interrupt command'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.
Restrictions
Terminal tabs must be set every eight positions.
Using as a filter with another command changes the terminal I/O
options. For example, terminal settings may not be restored correctly.
Files
Terminal information data base
Temporary file when input is from a pipe
See Alsocrypt(1), ed(1), grep(1), terminfo(5)pg(1)
