YAP(1)YAP(1)NAME
yap, more - yet another pager
SYNOPSISyap [-cnuq] [-n] [+command] [file ...]
DESCRIPTION
Yap is a program allowing the user to examine a continuous text one
screenful at a time on a video display terminal. It does so by pausing
after each screenful, waiting for the user to type a command. The com‐
mands are enumerated later. Yap's main feature is, that it can page
both forwards and backwards, even when reading from standard input.
The command line options are:
-n An integer which is the size (in lines) of a page (the initial
page-size.
-c Normally, yap will display each page by beginning at the top of
the screen and erasing each line just before it displays on it.
If your terminal cannot erase a line, yap will clear the screen
before it displays a page.
This avoids scrolling the screen, making it easier to read while
yap is writing. The -c option causes yap to scroll the screen
instead of beginning at the top of the screen. This is also
done if your terminal cannot either erase a line or clear the
screen.
-u Normally, yap handles underlining such as produced by nroff in a
manner appropriate to the particular terminal: if the terminal
can perform underlining well (t.i., the escape sequences for
underlining do not occupy space on the screen), yap will under‐
line underlined information in the input. The -u option
supresses this underlining.
-n Normally, yap also recognises escape sequences for stand-out
mode or underlining mode in the input, and knows how much space
these escape sequences will occupy on the screen, so that yap
will not fold lines erroneously. The -n option supresses this
pattern matching.
-q This option will cause yap to exit only on the "quit" command.
+command
command is taken to be an initial command to yap.
Yap looks in the YAP environment variable to pre-set flags. For
instance, if you prefer the -c mode of operation, just set the YAP
environment variable to -c.
The commands of yap can be bound to sequences of keystrokes. The envi‐
ronment variable YAPKEYS may contain the bindings in the form of a list
of colon-separated `name=sequence' pairs. The name is a short mnemonic
for the command, the sequence is the sequence of keystrokes to be typed
to invoke the command. This sequence may contain a ^X escape, which
means control-X, and a \X escape, which means X. The latter can be used
to get the characters `^', `\' and `:' in the sequence. There are two
keymaps available, the default one and a user-defined one. You can
switch between one and the other with the change keymap command.
The yap commands are described below. The mnemonics for the commands
are given in parentheses. The default key sequences (if any) are given
after the mnemonic. Every command takes an optional integer argument,
which may be typed before the command. Some commands just ignore it.
The integer argument is referred to as i. Usually, if i is not given,
it defaults to 1.
visit previous file (bf) P
Visit the i-th previous file given in the command line.
scroll one line up or go to line (bl) ^K or k
If i is not given, scroll one line up. Otherwise, i will be
interpreted as a line number. A page starting with the line
indicated will then be displayed.
bottom (bot) l or $
Go to the last line of the input.
display previous page (bp) -
Display the previous page, consisting of i lines, (or page-size
lines if no argument is given).
display previous page and set pagesize (bps) Z
Display the previous page, consisting of i lines, (or page-size
lines if no argument is given). If i is given, the page-size is
set to i.
scroll up (bs) ^B
Scroll up i lines (or scroll-size lines if i is not given. Ini‐
tially, the scroll-size is 11).
search backwards for pattern (bse) ?
Search backwards for the i-th occurrence of a regular expression
which will be prompted for. If there are less than i occur‐
rences of the expression, the position in the file remains
unchanged. Otherwise, a page is displayed, starting two lines
before the place where the expression was found. The user's
erase and kill characters may be used to edit the expression.
Erasing back past the first character cancels the search com‐
mand.
Note: Some systems do not have regex(3). On those systems,
searches are still supported, but regular expressions are not.
skip lines backwards (bsl) S
Skip i lines backwards and display a page.
skip pages backwards (bsp) F
Skip i pages backwards and display a page.
scroll up and set scrollsize (bss) b
Scroll up i lines (or scroll-size lines if i is not given. If i
is given, the scroll-size is set to i.
change key map (chm) X
Change from the current key map to the other (if there is one).
exchange current page and mark (exg) x
Set the mark to the current page, and display the previously
marked page.
visit next file (ff) N
Visit the i-th next file given in the command line.
scroll one line down or go to line (fl) ^J or ^M or j
If i is not given, scroll one line down. Otherwise, i will be
interpreted as a line number. A page starting with the line
indicated will then be displayed.
display next page (fp) <space>
Display the next page, consisting of i lines, (or page-size
lines if no argument is given).
display next page and set pagesize (fps) z
Display the next page, consisting of i lines, (or page-size
lines if no argument is given). If i is given, the page-size is
set to i.
scroll down (fs) ^D
Scroll down i lines (or scroll-size lines if no argument is
given).
search forwards for pattern (fse) /
Search forwards for the i-th occurrence of a regular expression
which will be prompted for. If there are less than i occur‐
rences of the expression, the position in the file remains
unchanged. Otherwise, a page is displayed, starting two lines
before the place where the expression was found. The user's
erase and kill characters may be used to edit the expression.
Erasing back past the first character cancels the search com‐
mand.
Note: Some systems do not have regex(3). On those systems,
searches are still supported, but regular expressions are not.
skip lines forwards (fsl) s
Skip i lines and display a page.
skip pages forwards (fsp) f
Skip i pages and display a page.
scroll down and set scrollsize (fss) d
Scroll down i lines (or scroll-size lines if i is not given. If
i is given, the scroll-size is set to i.
help (hlp) h
Give a short description of all commands that are bound to a key
sequence.
set a mark (mar) m
Set a mark on the current page.
repeat last search (nse) n
Search for the i-th occurrence of the last regular expression
entered, in the direction of the last search.
repeat last search in other direction (nsr) r
Search for the i-th occurrence of the last regular expression
entered, but in the other direction.
quit (qui) Q or q
Exit from yap.
redraw (red) ^L
Redraw the current page.
repeat (rep) .
Repeat the last command. This does not always make sense, so not
all commands can be repeated.
shell escape (shl) !
Invoke the shell with a command that will be prompted for. In
the command, the characters `%' and `!' are replaced with the
current file name and the previous shell command respectively.
The sequences `\%' and `\!' are replaced by `%' and `!' respec‐
tively. The user's erase and kill characters can be used to
edit the command. Erasing back past the first character cancels
the command.
pipe to shell command (pip) |
Pipe the current input file into a shell command that will be
prompted for. The comments given in the description of the
shell escape command apply here too.
go to mark (tom) '
Display the marked page.
top (top) ^^
Display a page starting with the first line of the input.
visit file (vis) e
Visit a new file. The filename will be prompted for. If you just
type a return, the current file is revisited.
write input to a file (wrf) w
Write the input to a file, whose name will be prompted for.
The commands take effect immediately, i.e., it is not necessary to type
a carriage return. Up to the time when the command sequence itself is
given, the user may give an interrupt to cancel the command being
formed.
AUTHOR
Ceriel J.H. Jacobs
SEE ALSOregex(3).
BUGS
Yap will find your terminal very stupid and act like it, if it has no
way of placing the cursor on the home position, or cannot either erase
a line or insert one.
In lines longer than about 2000 characters, a linefeed is silently
inserted.
The percentage, given in the prompt when yap reads from a file (and
knows it), is not always very accurate.
local YAP(1)
