PG(C) UNIX System V
Name
pg - file perusal filter for soft-copy terminals
Syntax
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 soft-copy terminal. (The
dash (-) command line option and/or NULL arguments indicate
that pg should read from the standard input.) Each screenful
is followed by a prompt. If you press the RETURN key,
another page is displayed; other possibilities are listed
below. This command is different from previous paginators
because it allows you to back up and review something that
has already passed.
To determine terminal attributes, pg scans the termcap(F)
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 Specifies 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.)
-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
a colon (:).
-c Homes the cursor and clears the screen before
displaying each page. This option is ignored if
clearscreen is not defined for this terminal
type in the termcap(F) data base.
-e Causes pg not to pause at the end of each file.
-f Inhibits pg from splitting lines. In the
absence of the -f option, pg splits lines longer
than the screen width, but some sequences of
characters in the displayed text (for example,
escape sequences for underlining) give
undesirable results.
-n Normally, commands must be terminated by
pressing the RETURN key (ASCII newline
character). This option causes an automatic end
of command as soon as a command letter is
entered.
-s Causes pg to display 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.
The responses that may be entered when pg pauses can be
divided into three categories: those that cause further
perusal, those that search, and those that modify the
perusal environment.
Commands which cause further perusal normally take a
preceding address (an optionally signed number indicating
the point from which further text should be displayed). pg
interprets this address 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 if no address is
provided.
The perusal commands and their defaults are as follows:
(+1)RETURNkey
Causes one page to be displayed. The address is
specified in pages.
(+1) l
With a signed address, causes pg to simulate scrolling
the screen, forward or backward, the number of lines
specified. With an unsigned address this command
displays a full screen of text beginning at the
specified line.
(+1) d or Ctrl-D
Simulates scrolling half a screen forward or backward.
The following perusal commands take no address:
. or Ctrl-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
ed(C) are available. They must always be terminated by a
newline character, 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 caret (^)
notation is useful for terminals which will not
properly handle the question mark (?).
After searching, pg displays the line found at the top of
the screen. You can modify this 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. Use the suffix t to
restore the original situation.
The following commands modify the environment of perusal:
in Begins perusing the ith next file in the command
line. The default value of i is 1.
ip Begins perusing the ith previous file in the command
line. The default value of i is 1.
iw Displays another window of text. If i is present,
set 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 character, even if
the -n option is specified.
h Help displays 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 character,
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 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(C), except that a header is printed before each
file (if there is more than one).
Example
To use pg to read system news, enter:
news | pg -p ``(Page %d):''
Files
/etc/termcap Terminal information data base
/tmp/pg* Temporary file when input is from a pipe
See Also
ed(C), grep(C), termcap(M)
Notes
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.
While waiting for terminal input, pg responds to "BREAK and
DEL" by terminating execution. Between prompts, however,
these signals interrupt pg's current task and place you in
prompt mode. Use these signals with caution when input is
being read from a pipe, since an interrupt is likely to
terminate the other commands in the pipeline.
The z and f commands used with more are available, and the
terminal slash (/), caret (^), or question mark (?) may be
omitted from the searching commands.
Standards Conformance
pg is conformant with:
AT&T SVID Issue 2, Select Code 307-127;
and The X/Open Portability Guide II of January 1987.
(printed 8/25/89) PG(C)