pg(1) General Commands Manual pg(1)
Name
pg - file perusal filter for soft-copy terminals
Syntax
pg [-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 desig-
nated 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 command 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 speci-
fies 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 backward.
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) 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?
Searches backwards for the ith (default i=1) occurrence of pattern. Searching begins immediately before the current page and con-
tinues to the beginning of the current file, without wrap-around. The circumflex (^) notation is useful for Adds 100 terminals
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 command 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 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 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.
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 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 contains 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 circumflex (^) 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 Also
crypt(1), ed(1), grep(1), terminfo(5)
pg(1)