|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|
|
PROLOG | NAME | SYNOPSIS | DESCRIPTION | OPTIONS | OPERANDS | STDIN | INPUT FILES | ENVIRONMENT VARIABLES | ASYNCHRONOUS EVENTS | STDOUT | STDERR | OUTPUT FILES | EXTENDED DESCRIPTION | EXIT STATUS | CONSEQUENCES OF ERRORS | APPLICATION USAGE | EXAMPLES | RATIONALE | FUTURE DIRECTIONS | SEE ALSO | COPYRIGHT |
|
|
|
MORE(1P) POSIX Programmer's Manual MORE(1P)
This manual page is part of the POSIX Programmer's Manual. The
Linux implementation of this interface may differ (consult the
corresponding Linux manual page for details of Linux behavior),
or the interface may not be implemented on Linux.
more — display files on a page-by-page basis
more [-ceisu] [-n number] [-p command] [-t tagstring] [file...]
The more utility shall read files and either write them to the
terminal on a page-by-page basis or filter them to standard
output. If standard output is not a terminal device, all input
files shall be copied to standard output in their entirety,
without modification, except as specified for the -s option. If
standard output is a terminal device, the files shall be written
a number of lines (one screenful) at a time under the control of
user commands. See the EXTENDED DESCRIPTION section.
Certain block-mode terminals do not have all the capabilities
necessary to support the complete more definition; they are
incapable of accepting commands that are not terminated with a
<newline>. Implementations that support such terminals shall
provide an operating mode to more in which all commands can be
terminated with a <newline> on those terminals. This mode:
* Shall be documented in the system documentation
* Shall, at invocation, inform the user of the terminal
deficiency that requires the <newline> usage and provide
instructions on how this warning can be suppressed in future
invocations
* Shall not be required for implementations supporting only
fully capable terminals
* Shall not affect commands already requiring <newline>
characters
* Shall not affect users on the capable terminals from using
more as described in this volume of POSIX.1‐2017
The more utility shall conform to the Base Definitions volume of
POSIX.1‐2017, Section 12.2, Utility Syntax Guidelines, except
that '+' may be recognized as an option delimiter as well as '-'.
The following options shall be supported:
-c If a screen is to be written that has no lines in
common with the current screen, or more is writing its
first screen, more shall not scroll the screen, but
instead shall redraw each line of the screen in turn,
from the top of the screen to the bottom. In addition,
if more is writing its first screen, the screen shall
be cleared. This option may be silently ignored on
devices with insufficient terminal capabilities.
-e Exit immediately after writing the last line of the
last file in the argument list; see the EXTENDED
DESCRIPTION section.
-i Perform pattern matching in searches without regard to
case; see the Base Definitions volume of POSIX.1‐2017,
Section 9.2, Regular Expression General Requirements.
-n number Specify the number of lines per screenful. The number
argument is a positive decimal integer. The -n option
shall override any values obtained from any other
source.
-p command
Each time a screen from a new file is displayed or
redisplayed (including as a result of more commands;
for example, :p), execute the more command(s) in the
command arguments in the order specified, as if entered
by the user after the first screen has been displayed.
No intermediate results shall be displayed (that is, if
the command is a movement to a screen different from
the normal first screen, only the screen resulting from
the command shall be displayed.) If any of the commands
fail for any reason, an informational message to this
effect shall be written, and no further commands
specified using the -p option shall be executed for
this file.
-s Behave as if consecutive empty lines were a single
empty line.
-t tagstring
Write the screenful of the file containing the tag
named by the tagstring argument. See the ctags(1p)
utility. The tags feature represented by -t tagstring
and the :t command is optional. It shall be provided on
any system that also provides a conforming
implementation of ctags; otherwise, the use of -t
produces undefined results.
The filename resulting from the -t option shall be
logically added as a prefix to the list of command line
files, as if specified by the user. If the tag named by
the tagstring argument is not found, it shall be an
error, and more shall take no further action.
If the tag specifies a line number, the first line of
the display shall contain the beginning of that line.
If the tag specifies a pattern, the first line of the
display shall contain the beginning of the matching
text from the first line of the file that contains that
pattern. If the line does not exist in the file or
matching text is not found, an informational message to
this effect shall be displayed, and more shall display
the default screen as if -t had not been specified.
If both the -t tagstring and -p command options are
given, the -t tagstring shall be processed first; that
is, the file and starting line for the display shall be
as specified by -t, and then the -p more command shall
be executed. If the line (matching text) specified by
the -t command does not exist (is not found), no -p
more command shall be executed for this file at any
time.
-u Treat a <backspace> as a printable control character,
displayed as an implementation-defined character
sequence (see the EXTENDED DESCRIPTION section),
suppressing backspacing and the special handling that
produces underlined or standout mode text on some
terminal types. Also, do not ignore a <carriage-
return> at the end of a line.
The following operand shall be supported:
file A pathname of an input file. If no file operands are
specified, the standard input shall be used. If a file
is '-', the standard input shall be read at that point
in the sequence.
The standard input shall be used only if no file operands are
specified, or if a file operand is '-'.
The input files being examined shall be text files. If standard
output is a terminal, standard error shall be used to read
commands from the user. If standard output is a terminal,
standard error is not readable, and command input is needed, more
may attempt to obtain user commands from the controlling terminal
(for example, /dev/tty); otherwise, more shall terminate with an
error indicating that it was unable to read user commands. If
standard output is not a terminal, no error shall result if
standard error cannot be opened for reading.
The following environment variables shall affect the execution of
more:
COLUMNS Override the system-selected horizontal display line
size. See the Base Definitions volume of POSIX.1‐2017,
Chapter 8, Environment Variables for valid values and
results when it is unset or null.
EDITOR Used by the v command to select an editor. See the
EXTENDED DESCRIPTION section.
LANG Provide a default value for the internationalization
variables that are unset or null. (See the Base
Definitions volume of POSIX.1‐2017, Section 8.2,
Internationalization Variables for the precedence of
internationalization variables used to determine the
values of locale categories.)
LC_ALL If set to a non-empty string value, override the values
of all the other internationalization variables.
LC_COLLATE
Determine the locale for the behavior of ranges,
equivalence classes, and multi-character collating
elements within regular expressions.
LC_CTYPE Determine the locale for the interpretation of
sequences of bytes of text data as characters (for
example, single-byte as opposed to multi-byte
characters in arguments and input files) and the
behavior of character classes within regular
expressions.
LC_MESSAGES
Determine the locale that should be used to affect the
format and contents of diagnostic messages written to
standard error and informative messages written to
standard output.
NLSPATH Determine the location of message catalogs for the
processing of LC_MESSAGES.
LINES Override the system-selected vertical screen size, used
as the number of lines in a screenful. See the Base
Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables for valid values and results when
it is unset or null. The -n option shall take
precedence over the LINES variable for determining the
number of lines in a screenful.
MORE Determine a string containing options described in the
OPTIONS section preceded with <hyphen-minus> characters
and <blank>-separated as on the command line. Any
command line options shall be processed after those in
the MORE variable, as if the command line were:
more $MORE options operands
The MORE variable shall take precedence over the TERM
and LINES variables for determining the number of lines
in a screenful.
TERM Determine the name of the terminal type. If this
variable is unset or null, an unspecified default
terminal type is used.
Default.
The standard output shall be used to write the contents of the
input files.
The standard error shall be used for diagnostic messages and user
commands (see the INPUT FILES section), and, if standard output
is a terminal device, to write a prompting string. The prompting
string shall appear on the screen line below the last line of the
file displayed in the current screenful. The prompt shall contain
the name of the file currently being examined and shall contain
an end-of-file indication and the name of the next file, if any,
when prompting at the end-of-file. If an error or informational
message is displayed, it is unspecified whether it is contained
in the prompt. If it is not contained in the prompt, it shall be
displayed and then the user shall be prompted for a continuation
character, at which point another message or the user prompt may
be displayed. The prompt is otherwise unspecified. It is
unspecified whether informational messages are written for other
user commands.
None.
The following section describes the behavior of more when the
standard output is a terminal device. If the standard output is
not a terminal device, no options other than -s shall have any
effect, and all input files shall be copied to standard output
otherwise unmodified, at which time more shall exit without
further action.
The number of lines available per screen shall be determined by
the -n option, if present, or by examining values in the
environment (see the ENVIRONMENT VARIABLES section). If neither
method yields a number, an unspecified number of lines shall be
used.
The maximum number of lines written shall be one less than this
number, because the screen line after the last line written shall
be used to write a user prompt and user input. If the number of
lines in the screen is less than two, the results are undefined.
It is unspecified whether user input is permitted to be longer
than the remainder of the single line where the prompt has been
written.
The number of columns available per line shall be determined by
examining values in the environment (see the ENVIRONMENT
VARIABLES section), with a default value as described in the Base
Definitions volume of POSIX.1‐2017, Chapter 8, Environment
Variables.
Lines that are longer than the display shall be folded; the
length at which folding occurs is unspecified, but should be
appropriate for the output device. Folding may occur between
glyphs of single characters that take up multiple display
columns.
When standard output is a terminal and -u is not specified, more
shall treat <backspace> and <carriage-return> characters
specially:
* A character, followed first by a sequence of n <backspace>
characters (where n is the same as the number of column
positions that the character occupies), then by n
<underscore> characters ('_'), shall cause that character to
be written as underlined text, if the terminal type supports
that. The n <underscore> characters, followed first by n
<backspace> characters, then any character with n column
positions, shall also cause that character to be written as
underlined text, if the terminal type supports that.
* A sequence of n <backspace> characters (where n is the same
as the number of column positions that the previous character
occupies) that appears between two identical printable
characters shall cause the first of those two characters to
be written as emboldened text (that is, visually brighter,
standout mode, or inverse-video mode), if the terminal type
supports that, and the second to be discarded. Immediately
subsequent occurrences of <backspace>/character pairs for
that same character shall also be discarded. (For example,
the sequence "a\ba\ba\ba" is interpreted as a single
emboldened 'a'.)
* The more utility shall logically discard all other
<backspace> characters from the line as well as the character
which precedes them, if any.
* A <carriage-return> at the end of a line shall be ignored,
rather than being written as a non-printable character, as
described in the next paragraph.
It is implementation-defined how other non-printable characters
are written. Implementations should use the same format that they
use for the ex print command; see the OPTIONS section within the
ed utility. It is unspecified whether a multi-column character
shall be separated if it crosses a display line boundary; it
shall not be discarded. The behavior is unspecified if the number
of columns on the display is less than the number of columns any
single character in the line being displayed would occupy.
When each new file is displayed (or redisplayed), more shall
write the first screen of the file. Once the initial screen has
been written, more shall prompt for a user command. If the
execution of the user command results in a screen that has lines
in common with the current screen, and the device has sufficient
terminal capabilities, more shall scroll the screen; otherwise,
it is unspecified whether the screen is scrolled or redrawn.
For all files but the last (including standard input if no file
was specified, and for the last file as well, if the -e option
was not specified), when more has written the last line in the
file, more shall prompt for a user command. This prompt shall
contain the name of the next file as well as an indication that
more has reached end-of-file. If the user command is f,
<control>‐F, <space>, j, <newline>, d, <control>‐D, or s, more
shall display the next file. Otherwise, if displaying the last
file, more shall exit. Otherwise, more shall execute the user
command specified.
Several of the commands described in this section display a
previous screen from the input stream. In the case that text is
being taken from a non-rewindable stream, such as a pipe, it is
implementation-defined how much backwards motion is supported. If
a command cannot be executed because of a limitation on backwards
motion, an error message to this effect shall be displayed, the
current screen shall not change, and the user shall be prompted
for another command.
If a command cannot be performed because there are insufficient
lines to display, more shall alert the terminal. If a command
cannot be performed because there are insufficient lines to
display or a / command fails: if the input is the standard input,
the last screen in the file may be displayed; otherwise, the
current file and screen shall not change, and the user shall be
prompted for another command.
The interactive commands in the following sections shall be
supported. Some commands can be preceded by a decimal integer,
called count in the following descriptions. If not specified with
the command, count shall default to 1. In the following
descriptions, pattern is a basic regular expression, as described
in the Base Definitions volume of POSIX.1‐2017, Section 9.3,
Basic Regular Expressions. The term ``examine'' is historical
usage meaning ``open the file for viewing''; for example, more
foo would be expressed as examining file foo.
In the following descriptions, unless otherwise specified, line
is a line in the more display, not a line from the file being
examined.
In the following descriptions, the current position refers to two
things:
1. The position of the current line on the screen
2. The line number (in the file) of the current line on the
screen
Usually, the line on the screen corresponding to the current
position is the third line on the screen. If this is not possible
(there are fewer than three lines to display or this is the first
page of the file, or it is the last page of the file), then the
current position is either the first or last line on the screen
as described later.
Help
Synopsis:
h
Write a summary of these commands and other implementation-
defined commands. The behavior shall be as if the more utility
were executed with the -e option on a file that contained the
summary information. The user shall be prompted as described
earlier in this section when end-of-file is reached. If the user
command is one of those specified to continue to the next file,
more shall return to the file and screen state from which the h
command was executed.
Scroll Forward One Screenful
Synopsis:
[count]f
[count]<control>-F
Scroll forward count lines, with a default of one screenful. If
count is more than the screen size, only the final screenful
shall be written.
Scroll Backward One Screenful
Synopsis:
[count]b
[count]<control>-B
Scroll backward count lines, with a default of one screenful (see
the -n option). If count is more than the screen size, only the
final screenful shall be written.
Scroll Forward One Line
Synopsis:
[count]<space>
[count]j
[count]<newline>
Scroll forward count lines. The default count for the <space>
shall be one screenful; for j and <newline>, one line. The entire
count lines shall be written, even if count is more than the
screen size.
Scroll Backward One Line
Synopsis:
[count]k
Scroll backward count lines. The entire count lines shall be
written, even if count is more than the screen size.
Scroll Forward One Half Screenful
Synopsis:
[count]d
[count]<control>-D
Scroll forward count lines, with a default of one half of the
screen size. If count is specified, it shall become the new
default for subsequent d, <control>‐D, and u commands.
Skip Forward One Line
Synopsis:
[count]s
Display the screenful beginning with the line count lines after
the last line on the current screen. If count would cause the
current position to be such that less than one screenful would be
written, the last screenful in the file shall be written.
Scroll Backward One Half Screenful
Synopsis:
[count]u
[count]<control>-U
Scroll backward count lines, with a default of one half of the
screen size. If count is specified, it shall become the new
default for subsequent d, <control>-D, u, and <control>-U
commands. The entire count lines shall be written, even if count
is more than the screen size.
Go to Beginning of File
Synopsis:
[count]g
Display the screenful beginning with line count.
Go to End-of-File
Synopsis:
[count]G
If count is specified, display the screenful beginning with the
line count. Otherwise, display the last screenful of the file.
Refresh the Screen
Synopsis:
r
<control>-L
Refresh the screen.
Discard and Refresh
Synopsis:
R
Refresh the screen, discarding any buffered input. If the current
file is non-seekable, buffered input shall not be discarded and
the R command shall be equivalent to the r command.
Mark Position
Synopsis:
mletter
Mark the current position with the letter named by letter, where
letter represents the name of one of the lowercase letters of the
portable character set. When a new file is examined, all marks
may be lost.
Return to Mark
Synopsis:
'letter
Return to the position that was previously marked with the letter
named by letter, making that line the current position.
Return to Previous Position
Synopsis:
''
Return to the position from which the last large movement command
was executed (where a ``large movement'' is defined as any
movement of more than a screenful of lines). If no such movements
have been made, return to the beginning of the file.
Search Forward for Pattern
Synopsis:
[count]/[!]pattern<newline>
Display the screenful beginning with the countth line containing
the pattern. The search shall start after the first line
currently displayed. The null regular expression ('/' followed by
a <newline>) shall repeat the search using the previous regular
expression, with a default count. If the character '!' is
included, the matching lines shall be those that do not contain
the pattern. If no match is found for the pattern, a message to
that effect shall be displayed.
Search Backward for Pattern
Synopsis:
[count]?[!]pattern<newline>
Display the screenful beginning with the countth previous line
containing the pattern. The search shall start on the last line
before the first line currently displayed. The null regular
expression ('?' followed by a <newline>) shall repeat the search
using the previous regular expression, with a default count. If
the character '!' is included, matching lines shall be those
that do not contain the pattern. If no match is found for the
pattern, a message to that effect shall be displayed.
Repeat Search
Synopsis:
[count]n
Repeat the previous search for countth line containing the last
pattern (or not containing the last pattern, if the previous
search was "/!" or "?!").
Repeat Search in Reverse
Synopsis:
[count]N
Repeat the search in the opposite direction of the previous
search for the countth line containing the last pattern (or not
containing the last pattern, if the previous search was "/!" or
"?!").
Examine New File
Synopsis:
:e [filename]<newline>
Examine a new file. If the filename argument is not specified,
the current file (see the :n and :p commands below) shall be re-
examined. The filename shall be subjected to the process of shell
word expansions (see Section 2.6, Word Expansions); if more than
a single pathname results, the effects are unspecified. If
filename is a <number-sign> ('#'), the previously examined file
shall be re-examined. If filename is not accessible for any
reason (including that it is a non-seekable file), an error
message to this effect shall be displayed and the current file
and screen shall not change.
Examine Next File
Synopsis:
[count]:n
Examine the next file. If a number count is specified, the
countth next file shall be examined. If filename refers to a non-
seekable file, the results are unspecified.
Examine Previous File
Synopsis:
[count]:p
Examine the previous file. If a number count is specified, the
countth previous file shall be examined. If filename refers to a
non-seekable file, the results are unspecified.
Go to Tag
Synopsis:
:t tagstring<newline>
If the file containing the tag named by the tagstring argument is
not the current file, examine the file, as if the :e command was
executed with that file as the argument. Otherwise, or in
addition, display the screenful beginning with the tag, as
described for the -t option (see the OPTIONS section). If the
ctags utility is not supported by the system, the use of :t
produces undefined results.
Invoke Editor
Synopsis:
v
Invoke an editor to edit the current file being examined. If
standard input is being examined, the results are unspecified.
The name of the editor shall be taken from the environment
variable EDITOR, or shall default to vi. If the last pathname
component in EDITOR is either vi or ex, the editor shall be
invoked with a -c linenumber command line argument, where
linenumber is the line number of the file line containing the
display line currently displayed as the first line of the screen.
It is implementation-defined whether line-setting options are
passed to editors other than vi and ex.
When the editor exits, more shall resume with the same file and
screen as when the editor was invoked.
Display Position
Synopsis:
=
<control>-G
Write a message for which the information references the first
byte of the line after the last line of the file on the screen.
This message shall include the name of the file currently being
examined, its number relative to the total number of files there
are to examine, the line number in the file, the byte number and
the total bytes in the file, and what percentage of the file
precedes the current position. If more is reading from standard
input, or the file is shorter than a single screen, the line
number, the byte number, the total bytes, and the percentage need
not be written.
Quit
Synopsis:
q
:q
ZZ
Exit more.
The following exit values shall be returned:
0 Successful completion.
>0 An error occurred.
If an error is encountered accessing a file when using the :n
command, more shall attempt to examine the next file in the
argument list, but the final exit status shall be affected. If an
error is encountered accessing a file via the :p command, more
shall attempt to examine the previous file in the argument list,
but the final exit status shall be affected. If an error is
encountered accessing a file via the :e command, more shall
remain in the current file and the final exit status shall not be
affected.
The following sections are informative.
When the standard output is not a terminal, only the -s filter-
modification option is effective. This is based on historical
practice. For example, a typical implementation of man pipes its
output through more -s to squeeze excess white space for terminal
users. When man is piped to lp, however, it is undesirable for
this squeezing to happen.
The -p allows arbitrary commands to be executed at the start of
each file. Examples are:
more -p G file1 file2
Examine each file starting with its last screenful.
more -p 100 file1 file2
Examine each file starting with line 100 in the current
position (usually the third line, so line 98 would be the
first line written).
more -p /100 file1 file2
Examine each file starting with the first line containing
the string "100" in the current position
The more utility, available in BSD and BSD-derived systems, was
chosen as the prototype for the POSIX file display program since
it is more widely available than either the public-domain program
less or than pg, a pager provided in System V. The 4.4 BSD more
is the model for the features selected; it is almost fully
upwards-compatible from the 4.3 BSD version in wide use and has
become more amenable for vi users. Several features originally
derived from various file editors, found in both less and pg,
have been added to this volume of POSIX.1‐2017 as they have
proved extremely popular with users.
There are inconsistencies between more and vi that result from
historical practice. For example, the single-character commands
h, f, b, and <space> are screen movers in more, but cursor movers
in vi. These inconsistencies were maintained because the cursor
movements are not applicable to more and the powerful
functionality achieved without the use of the control key
justifies the differences.
The tags interface has been included in a program that is not a
text editor because it promotes another degree of consistent
operation with vi. It is conceivable that the paging environment
of more would be superior for browsing source code files in some
circumstances.
The operating mode referred to for block-mode terminals
effectively adds a <newline> to each Synopsis line that currently
has none. So, for example, d<newline> would page one screenful.
The mode could be triggered by a command line option, environment
variable, or some other method. The details are not imposed by
this volume of POSIX.1‐2017 because there are so few systems
known to support such terminals. Nevertheless, it was considered
that all systems should be able to support more given the
exception cited for this small community of terminals because, in
comparison to vi, the cursor movements are few and the command
set relatively amenable to the optional <newline> characters.
Some versions of more provide a shell escaping mechanism similar
to the ex ! command. The standard developers did not consider
that this was necessary in a paginator, particularly given the
wide acceptance of multiple window terminals and job control
features. (They chose to retain such features in the editors and
mailx because the shell interaction also gives an opportunity to
modify the editing buffer, which is not applicable to more.)
The -p (position) option replaces the + command because of the
Utility Syntax Guidelines. The +command option is no longer
specified by POSIX.1‐2008 but may be present in some
implementations. In early proposals, it took a pattern argument,
but historical less provided the more general facility of a
command. It would have been desirable to use the same -c as ex
and vi, but the letter was already in use.
The text stating ``from a non-rewindable stream ...
implementations may limit the amount of backwards motion
supported'' would allow an implementation that permitted no
backwards motion beyond text already on the screen. It was not
possible to require a minimum amount of backwards motion that
would be effective for all conceivable device types. The
implementation should allow the user to back up as far as
possible, within device and reasonable memory allocation
constraints.
Historically, non-printable characters were displayed using the
ARPA standard mappings, which are as follows:
1. Printable characters are left alone.
2. Control characters less than \177 are represented as followed
by the character offset from the '@' character in the ASCII
map; for example, \007 is represented as 'G'.
3. \177 is represented as followed by '?'.
The display of characters having their eighth bit set was less
standard. Existing implementations use hex (0x00), octal (\000),
and a meta-bit display. (The latter displayed characters with
their eighth bit set as the two characters "M-", followed by the
seven-bit display as described previously.) The latter probably
has the best claim to historical practice because it was used
with the -v option of 4 BSD and 4 BSD-derived versions of the cat
utility since 1980.
No specific display format is required by POSIX.1‐2008.
Implementations are encouraged to conform to historic practice in
the absence of any strong reason to diverge.
None.
Chapter 2, Shell Command Language, ctags(1p), ed(1p), ex(1p),
vi(1p)
The Base Definitions volume of POSIX.1‐2017, Chapter 8,
Environment Variables, Section 9.2, Regular Expression General
Requirements, Section 9.3, Basic Regular Expressions, Section
12.2, Utility Syntax Guidelines
Portions of this text are reprinted and reproduced in electronic
form from IEEE Std 1003.1-2017, Standard for Information
Technology -- Portable Operating System Interface (POSIX), The
Open Group Base Specifications Issue 7, 2018 Edition, Copyright
(C) 2018 by the Institute of Electrical and Electronics
Engineers, Inc and The Open Group. In the event of any
discrepancy between this version and the original IEEE and The
Open Group Standard, the original IEEE and The Open Group
Standard is the referee document. The original Standard can be
obtained online at http://www.opengroup.org/unix/online.html .
Any typographical or formatting errors that appear in this page
are most likely to have been introduced during the conversion of
the source files to man page format. To report such errors, see
https://www.kernel.org/doc/man-pages/reporting_bugs.html .
IEEE/The Open Group 2017 MORE(1P)
Pages that refer to this page: cat(1p), mailx(1p), man(1p)
|
HTML rendering created 2024-06-26 by Michael Kerrisk, author of The Linux Programming Interface. For details of in-depth Linux/UNIX system programming training courses that I teach, look here. Hosting by jambit GmbH. |
|