diff options
Diffstat (limited to 'doc/ed.texi')
| -rw-r--r-- | doc/ed.texi | 1006 |
1 files changed, 1006 insertions, 0 deletions
diff --git a/doc/ed.texi b/doc/ed.texi new file mode 100644 index 0000000..6afc69c --- /dev/null +++ b/doc/ed.texi @@ -0,0 +1,1006 @@ +\input texinfo @c -*-texinfo-*- +@c %**start of header +@setfilename ed.info +@documentencoding ISO-8859-15 +@settitle GNU @command{ed} Manual +@finalout +@c %**end of header + +@set UPDATED 30 March 2015 +@set VERSION 1.11 + +@dircategory Basics +@direntry +* Ed: (ed). The GNU line editor +@end direntry + +@copying +Copyright @copyright{} 1993, 1994, 2006-2015 +Free Software Foundation, Inc. + +Permission is granted to copy, distribute and/or modify this document +under the terms of the GNU Free Documentation License, Version 1.3 or +any later version published by the Free Software Foundation; with no +Invariant Sections, no Front-Cover Texts, and no Back-Cover Texts. +@end copying + +@ifnothtml +@titlepage +@title GNU ed +@subtitle The GNU line editor +@subtitle for GNU ed version @value{VERSION}, @value{UPDATED} +@author by Andrew L. Moore, François Pinard, and Antonio Diaz Diaz + +@page +@vskip 0pt plus 1filll +@insertcopying +@end titlepage + +@contents +@end ifnothtml + +@ifnottex +@node Top +@top The GNU ed line editor + +This manual is for GNU ed (version @value{VERSION}, @value{UPDATED}). + +@sp 1 +GNU ed is a line-oriented text editor. It is used to create, display, +modify and otherwise manipulate text files, both interactively and via +shell scripts. A restricted version of ed, red, can only edit files in +the current directory and cannot execute shell commands. Ed is the +"standard" text editor in the sense that it is the original editor for +Unix, and thus widely available. For most purposes, however, it is +superseded by full-screen editors such as GNU Emacs or GNU Moe. +@end ifnottex + +@menu +* Overview:: Overview of the @command{ed} command +* Introduction to line editing:: Getting started with GNU @command{ed} +* Invoking ed:: Command line interface +* Line addressing:: Specifying lines/ranges in the buffer +* Regular expressions:: Patterns for selecting text +* Commands:: Commands recognized by GNU @command{ed} +* Limitations:: Intrinsic limits of GNU @command{ed} +* Diagnostics:: GNU @command{ed} error handling +* Problems:: Reporting bugs +* GNU Free Documentation License:: How you can copy and share this manual +@end menu + +@sp 1 +@insertcopying + + +@node Overview +@chapter Overview + +@command{ed} is a line-oriented text editor. It is used to create, +display, modify and otherwise manipulate text files. @command{red} is a +restricted @command{ed}: it can only edit files in the current directory +and cannot execute shell commands. + +If invoked with a @var{file} argument, then a copy of @var{file} is read +into the editor's buffer. Changes are made to this copy and not directly +to @var{file} itself. Upon quitting @command{ed}, any changes not +explicitly saved with a @samp{w} command are lost. + +Editing is done in two distinct modes: @dfn{command} and @dfn{input}. +When first invoked, @command{ed} is in command mode. In this mode +commands are read from the standard input and executed to manipulate the +contents of the editor buffer. A typical command might look like: + +@example +,s/@var{old}/@var{new}/g +@end example + +which replaces all occurences of the string @var{old} with @var{new}. + +When an input command, such as @samp{a} (append), @samp{i} (insert) or +@samp{c} (change), is given, @command{ed} enters input mode. This is the +primary means of adding text to a file. In this mode, no commands are +available; instead, the standard input is written directly to the editor +buffer. A @dfn{line} consists of the text up to and including a +@key{newline} character. Input mode is terminated by entering a single +period (@samp{.}) on a line. + +All @command{ed} commands operate on whole lines or ranges of lines; +e.g., the @samp{d} command deletes lines; the @samp{m} command moves +lines, and so on. It is possible to modify only a portion of a line by +means of replacement, as in the example above. However even here, the +@samp{s} command is applied to whole lines at a time. + +In general, @command{ed} commands consist of zero or more line +addresses, followed by a single character command and possibly +additional parameters; i.e., commands have the structure: + +@example +[@var{address} [,@var{address}]]@var{command}[@var{parameters}] +@end example + +The @var{address}es indicate the line or range of lines to be affected +by the command. If fewer addresses are given than the command accepts, +then default addresses are supplied. + + +@node Introduction to line editing +@chapter Introduction to line editing + +@command{ed} was created, along with the Unix operating system, by Ken +Thompson and Dennis Ritchie. It is the refinement of its more complex, +programmable predecessor, @cite{QED}, to which Thompson and Ritchie had +already added pattern matching capabilities (@pxref{Regular +expressions}). + +For the purposes of this tutorial, a working knowledge of the Unix shell +@command{sh} and the Unix file system is recommended, since @command{ed} +is designed to interact closely with them. +@ifnothtml +(@xref{Top,GNU bash manual,,bash}, +@end ifnothtml +@ifhtml +(See the +@uref{http://www.gnu.org/software/bash/manual/,,bash manual} +@end ifhtml +for details about bash). + +The principal difference between line editors and display editors is +that display editors provide instant feedback to user commands, whereas +line editors require sometimes lengthy input before any effects are +seen. The advantage of instant feedback, of course, is that if a mistake +is made, it can be corrected immediately, before more damage is done. +Editing in @command{ed} requires more strategy and forethought; but if +you are up to the task, it can be quite efficient. + +Much of the @command{ed} command syntax is shared with other Unix +utilities. + +As with the shell, @key{RETURN} (the carriage-return key) enters a line +of input. So when we speak of "entering" a command or some text in +@command{ed}, @key{RETURN} is implied at the end of each line. Prior to +typing @key{RETURN}, corrections to the line may be made by typing +either @key{BACKSPACE} (sometimes labeled @key{DELETE} or @key{DEL}) to +erase characters backwards, or @key{CONTROL}-u (i.e., hold the CONTROL +key and type u) to erase the whole line. + +When @command{ed} first opens, it expects to be told what to do but +doesn't prompt us like the shell. So let's begin by telling @command{ed} +to do so with the @key{P} (@dfn{prompt}) command: + +@example +$ ed +P +* +@end example + +By default, @command{ed} uses asterisk (@samp{*}) as command prompt to +avoid confusion with the shell command prompt (@samp{$}). + +We can run Unix shell (@command{sh}) commands from inside @command{ed} +by prefixing them with @key{!} (exclamation mark, aka "bang"). For +example: + +@example +*!date +Mon Jun 26 10:08:41 PDT 2006 +! +*!for s in hello world; do echo $s; done +hello +world +! +* +@end example + +So far, this is no different from running commands in the Unix shell. +But let's say we want to edit the output of a command, or save it to a +file. First we must capture the command output to a temporary location +called a @dfn{buffer} where @command{ed} can access it. This is done +with @command{ed}'s @key{r} command (mnemonic: @dfn{read}): + +@example +*r !cal -m +137 +* +@end example + +Here @command{ed} is telling us that it has just read 137 characters +into the editor buffer - i.e., the output of the @command{cal} command, +which prints a simple ASCII calendar. To display the buffer contents we +issue the @key{p} (@dfn{print}) command (not to be confused with the +prompt command, which is uppercase!). To indicate the range of lines in +the buffer that should be printed, we prefix the command with @key{,} +(comma) which is shorthand for "the whole buffer": + +@example +*,p + June 2006 +Mo Tu We Th Fr Sa Su + 1 2 3 4 + 5 6 7 8 9 10 11 +12 13 14 15 16 17 18 +19 20 21 22 23 24 25 +26 27 28 29 30 + +* +@end example + +Now let's write the buffer contents to a file named @code{junk} with the +@key{w} (@dfn{write}) command. Again, we use the @key{,} prefix to +indicate that it's the whole buffer we want: + +@example +*,w junk +137 +* +@end example + +Need we say? It's good practice to frequently write the buffer contents, +since unwritten changes to the buffer will be lost when we exit +@command{ed}. + +The sample sessions below illustrate some basic concepts of line editing +with @command{ed}. We begin by creating a file, @samp{sonnet}, with some +help from Shakespeare. As with the shell, all input to @command{ed} must +be followed by a @key{newline} character. Comments begin with a @samp{#}. + +@example +$ ed +# The 'a' command is for appending text to the editor buffer. +a +No more be grieved at that which thou hast done. +Roses have thorns, and filvers foutians mud. +Clouds and eclipses stain both moon and sun, +And loathsome canker lives in sweetest bud. +. +# Entering a single period on a line returns @command{ed} to command mode. +# Now write the buffer to the file @samp{sonnet} and quit: +w sonnet +183 +# @command{ed} reports the number of characters written. +q +$ ls -l +total 2 +-rw-rw-r-- 1 alm 183 Nov 10 01:16 sonnet +$ +@end example + +In the next example, some typos are corrected in the file @samp{sonnet}. + +@example +$ ed sonnet +183 +# Begin by printing the buffer to the terminal with the @samp{p} command. +# The ',' means "all lines". +,p +No more be grieved at that which thou hast done. +Roses have thorns, and filvers foutians mud. +Clouds and eclipses stain both moon and sun, +And loathsome canker lives in sweetest bud. +# Select line 2 for editing. +2 +Roses have thorns, and filvers foutians mud. +# Use the substitute command, @samp{s}, to replace 'filvers' with 'silver', +# and print the result. +s/filvers/silver/p +Roses have thorns, and silver foutians mud. +# And correct the spelling of 'fountains'. +s/utia/untai/p +Roses have thorns, and silver fountains mud. +w sonnet +183 +q +$ +@end example + +Since @command{ed} is line-oriented, we have to tell it which line, or +range of lines we want to edit. In the above example, we do this by +specifying the line's number, or sequence in the buffer. Alternatively, +we could have specified a unique string in the line, e.g., +@samp{/filvers/}, where the @samp{/}s delimit the string in question. +Subsequent commands affect only the selected line, a.k.a. the +@dfn{current} line. Portions of that line are then replaced with the +substitute command, whose syntax is @samp{s/@var{old}/@var{new}/}. + +Although @command{ed} accepts only one command per line, the print +command @samp{p} is an exception, and may be appended to the end of most +commands. + +In the next example, a title is added to our sonnet. + +@example +$ ed sonnet +183 +a + Sonnet #50 +. +,p +No more be grieved at that which thou hast done. +Roses have thorns, and silver fountains mud. +Clouds and eclipses stain both moon and sun, +And loathsome canker lives in sweetest bud. + Sonnet #50 +# The title got appended to the end; we should have used '0a' +# to append "before the first line". +# Move the title to its proper place. +5m0p + Sonnet #50 +# The title is now the first line, and the current line has been +# set to this line as well. +,p + Sonnet #50 +No more be grieved at that which thou hast done. +Roses have thorns, and silver fountains mud. +Clouds and eclipses stain both moon and sun, +And loathsome canker lives in sweetest bud. +wq sonnet +195 +$ +@end example + +When @command{ed} opens a file, the current line is initially set to the +last line of that file. Similarly, the move command @samp{m} sets the +current line to the last line moved. + +Related programs or routines are @command{vi (1)}, @command{sed (1)}, +@command{regex (3)}, @command{sh (1)}. Relevant documents +are: + +@quotation +Unix User's Manual Supplementary Documents: 12 --- 13 +@end quotation + +@quotation +B. W. Kernighan and P. J. Plauger: "Software Tools in Pascal", +Addison-Wesley, 1981. +@end quotation + + +@node Invoking ed +@chapter Invoking ed + +The format for running @command{ed} is: + +@example +ed [@var{options}] [@var{file}] +red [@var{options}] [@var{file}] +@end example + +@var{file} specifies the name of a file to read. If @var{file} is +prefixed with a bang (!), then it is interpreted as a shell command. In +this case, what is read is the standard output of @var{file} executed +via @command{sh (1)}. To read a file whose name begins with a bang, +prefix the name with a backslash (@kbd{\}). The default filename is set +to @var{file} only if it is not prefixed with a bang. + +@command{ed} supports the following options: + +@table @code +@item -h +@itemx --help +Print an informative help message describing the options and exit. + +@item -V +@itemx --version +Print the version number of @command{ed} on the standard output and exit. + +@item -G +@itemx --traditional +Forces backwards compatibility. This affects the behavior of the +@command{ed} commands @samp{G}, @samp{V}, @samp{f}, @samp{l}, @samp{m}, +@samp{t} and @samp{!!}. If the default behavior of these commands does +not seem familiar, then try invoking @command{ed} with this switch. + +@item -l +@itemx --loose-exit-status +Do not exit with bad status if a command happens to "fail" (for example +if a substitution command finds nothing to replace). This can be useful +when @command{ed} is invoked as the editor for crontab. + +@item -p @var{string} +@itemx --prompt=@var{string} +Specifies a command prompt. This may be toggled on and off with the +@samp{P} command. + +@item -r +@itemx --restricted +Run in restricted mode. This mode disables edition of files out of the +current directory and execution of shell commands. + +@item -s +@itemx --quiet +@itemx --silent +Suppresses diagnostics. This should be used if @command{ed}'s standard +input is from a script. + +@item -v +@itemx --verbose +Verbose mode. This may be toggled on and off with the @samp{H} command. + +@end table + + +@node Line addressing +@chapter Line addressing + +An address represents the number of a line in the buffer. @command{ed} +maintains a @dfn{current address} which is typically supplied to +commands as the default address when none is specified. When a file is +first read, the current address is set to the last line of the file. In +general, the current address is set to the last line affected by a +command. + +One exception to the rule that addresses represent line numbers is the +address @samp{0} (zero). This means "before the first line", and is +valid wherever it makes sense. + +An address range is two addresses separated either by a comma (@samp{,}) +or a semicolon (@samp{;}). The value of the first address in a range +cannot exceed the value of the second. If only one address is given in a +range, then the second address is set to the given address. If an +@var{n}-tuple of addresses is given where @var{n} > 2, then the +corresponding range is determined by the last two addresses in the +@var{n}-tuple. If only one address is expected, then the last address is +used. + +In a semicolon-delimited range, the current address (@samp{.}) is set to +the first address before the second address is calculated. This feature +can be used to set the starting line for searches. + +A line address is constructed as follows: + +@table @code +@item . +The current line (address) in the buffer. + +@item $ +The last line in the buffer. + +@item @var{n} +The @var{n}th line in the buffer, where @var{n} is a number in the range +@samp{0,$}. + +@item +@var{n} +The @var{n}th next line, where @var{n} is a non-negative number. + +@item -@var{n} +The @var{n}th previous line, where @var{n} is a non-negative number. + +@item + +The next line. This is equivalent to @samp{+1} and may be repeated with +cumulative effect. + +@item - +The previous line. This is equivalent to @samp{-1} and may be repeated +with cumulative effect. + +@item , +The first through last lines in the buffer. This is equivalent to the +address range @samp{1,$}. + +@item ; +The current through last lines in the buffer. This is equivalent to the +address range @samp{.,$}. + +@item /@var{re}/ +The next line containing the regular expression @var{re}. The search +wraps to the beginning of the buffer and continues down to the current +line, if necessary. @samp{//} repeats the last search. + +@item ?@var{re}? +The previous line containing the regular expression @var{re}. The search +wraps to the end of the buffer and continues up to the current line, if +necessary. @samp{??} repeats the last search. + +@item 'x +The apostrophe-x character pair addresses the line previously marked by +a @samp{k} (mark) command, where @samp{x} is a lower case letter from +the portable character set. + +@end table + +Addresses can be followed by one or more address offsets, optionally +separated by whitespace. Offsets are constructed as follows: + +@itemize @bullet +@item +A number adds the indicated number of lines to the address. + +@item +@samp{+} or @samp{-} followed by a number adds or subtracts the +indicated number of lines to or from the address. + +@item +@samp{+} or @samp{-} not followed by a number adds or subtracts 1 to or +from the address. + +@end itemize + + +@node Regular expressions +@chapter Regular expressions + +Regular expressions are patterns used in selecting text. For example, +the @command{ed} command + +@example +g/@var{string}/ +@end example + +@noindent +prints all lines containing @var{string}. Regular expressions are also +used by the @samp{s} command for selecting old text to be replaced with +new text. + +In addition to a specifying string literals, regular expressions can +represent classes of strings. Strings thus represented are said to be +matched by the corresponding regular expression. If it is possible for a +regular expression to match several strings in a line, then the +left-most longest match is the one selected. + +The following symbols are used in constructing regular expressions: + +@table @code + +@item @var{c} +Any character @var{c} not listed below, including @samp{@{}, @samp{@}}, +@samp{(}, @samp{)}, @samp{<} and @samp{>}, matches itself. + +@item \@var{c} +Any backslash-escaped character @var{c}, other than @samp{@{}, +@samp{@}}, @samp{(}, @samp{)}, @samp{<}, @samp{>}, @samp{b}, @samp{B}, +@samp{w}, @samp{W}, @samp{+} and @samp{?}, matches itself. + +@item . +Matches any single character. + +@item [@var{char-class}] +Matches any single character in @var{char-class}. To include a @samp{]} +in @var{char-class}, it must be the first character. A range of +characters may be specified by separating the end characters of the +range with a @samp{-}, e.g., @samp{a-z} specifies the lower case +characters. The following literal expressions can also be used in +@var{char-class} to specify sets of characters: + +@example +[:alnum:] [:cntrl:] [:lower:] [:space:] +[:alpha:] [:digit:] [:print:] [:upper:] +[:blank:] [:graph:] [:punct:] [:xdigit:] +@end example + +If @samp{-} appears as the first or last character of @var{char-class}, +then it matches itself. All other characters in @var{char-class} match +themselves. + +Patterns in +@var{char-class} +of the form: +@example +[.@var{col-elm}.] +[=@var{col-elm}=] +@end example + +@noindent +where @var{col-elm} is a @dfn{collating element} are interpreted +according to @code{locale (5)}. See +@code{regex (3)} for an explanation of these constructs. + +@item [^@var{char-class}] +Matches any single character, other than newline, not in +@var{char-class}. @var{char-class} is defined as above. + +@item ^ +If @samp{^} is the first character of a regular expression, then it +anchors the regular expression to the beginning of a line. Otherwise, +it matches itself. + +@item $ +If @samp{$} is the last character of a regular expression, it anchors +the regular expression to the end of a line. Otherwise, it matches +itself. + +@item \(@var{re}\) +Defines a (possibly null) subexpression @var{re}. Subexpressions may be +nested. A subsequent backreference of the form @samp{\@var{n}}, where +@var{n} is a number in the range [1,9], expands to the text matched by +the @var{n}th subexpression. For example, the regular expression +@samp{\(a.c\)\1} matches the string @samp{abcabc}, but not +@samp{abcadc}. Subexpressions are ordered relative to their left +delimiter. + +@item * +Matches the single character regular expression or subexpression +immediately preceding it zero or more times. If @samp{*} is the first +character of a regular expression or subexpression, then it matches +itself. The @samp{*} operator sometimes yields unexpected results. For +example, the regular expression @samp{b*} matches the beginning of the +string @samp{abbb}, as opposed to the substring @samp{bbb}, since a null +match is the only left-most match. + +@item \@{@var{n},@var{m}\@} +@itemx \@{@var{n},\@} +@itemx \@{@var{n}\@} +Matches the single character regular expression or subexpression +immediately preceding it at least @var{n} and at most @var{m} times. If +@var{m} is omitted, then it matches at least @var{n} times. If the comma +is also omitted, then it matches exactly @var{n} times. If any of these +forms occurs first in a regular expression or subexpression, then it is +interpreted literally (i.e., the regular expression @samp{\@{2\@}} +matches the string @samp{@{2@}}, and so on). + +@item \< +@itemx \> +Anchors the single character regular expression or subexpression +immediately following it to the beginning (in the case of @samp{\<}) or +ending (in the case of @samp{\>}) of a @dfn{word}, i.e., in ASCII, a +maximal string of alphanumeric characters, including the underscore (_). + +@end table + +The following extended operators are preceded by a backslash @samp{\} to +distinguish them from traditional @command{ed} syntax. + +@table @code + +@item \` +@itemx \' +Unconditionally matches the beginning @samp{\`} or ending @samp{\'} of a line. + +@item \? +Optionally matches the single character regular expression or +subexpression immediately preceding it. For example, the regular +expression @samp{a[bd]\?c} matches the strings @samp{abc}, @samp{adc} +and @samp{ac}. If @samp{\?} occurs at the beginning of a regular +expressions or subexpression, then it matches a literal @samp{?}. + +@item \+ +Matches the single character regular expression or subexpression +immediately preceding it one or more times. So the regular expression +@samp{a+} is shorthand for @samp{aa*}. If @samp{\+} occurs at the +beginning of a regular expression or subexpression, then it matches a +literal @samp{+}. + +@item \b +Matches the beginning or ending (null string) of a word. Thus the +regular expression @samp{\bhello\b} is equivalent to @samp{\<hello\>}. +However, @samp{\b\b} is a valid regular expression whereas @samp{\<\>} +is not. + +@item \B +Matches (a null string) inside a word. + +@item \w +Matches any character in a word. + +@item \W +Matches any character not in a word. + +@end table + + +@node Commands +@chapter Commands + +All @command{ed} commands are single characters, though some require +additonal parameters. If a command's parameters extend over several +lines, then each line except for the last must be terminated with a +backslash (@samp{\}). + +In general, at most one command is allowed per line. However, most +commands accept a print suffix, which is any of @samp{p} (print), +@samp{l} (list), or @samp{n} (enumerate), to print the last line +affected by the command. + +An interrupt (typically @key{Control-C}) has the effect of aborting the +current command and returning the editor to command mode. + +@command{ed} recognizes the following commands. The commands are shown +together with the default address or address range supplied if none is +specified (in parenthesis). + +@table @code + +@item (.)a +Appends text to the buffer after the addressed line, which may be the +address @samp{0} (zero). Text is entered in input mode. The current +address is set to last line entered. + +@item (.,.)c +Changes lines in the buffer. The addressed lines are deleted from the +buffer, and text is appended in their place. Text is entered in input +mode. The current address is set to last line entered. + +@item (.,.)d +Deletes the addressed lines from the buffer. If there is a line after +the deleted range, then the current address is set to this line. +Otherwise the current address is set to the line before the deleted +range. + +@item e @var{file} +Edits @var{file}, and sets the default filename. If @var{file} is not +specified, then the default filename is used. Any lines in the buffer +are deleted before the new file is read. The current address is set to +the last line read. + +@item e !@var{command} +Edits the standard output of @samp{!@var{command}}, (see the @samp{!} +command below). The default filename is unchanged. Any lines in the +buffer are deleted before the output of @var{command} is read. The +current address is set to the last line read. + +@item E @var{file} +Edits @var{file} unconditionally. This is similar to the @samp{e} +command, except that unwritten changes are discarded without warning. +The current address is set to the last line read. + +@item f @var{file} +Sets the default filename to @var{file}. If @var{file} is not specified, +then the default unescaped filename is printed. + +@item (1,$)g /@var{re}/@var{command-list} +Global command. Applies @var{command-list} to each of the addressed +lines matching a regular expression @var{re}. The current address is set +to the line currently matched before @var{command-list} is executed. At +the end of the @samp{g} command, the current address is set to the last +line affected by @var{command-list}. + +At least the first command of @var{command-list} must appear on the same +line as the @samp{g} command. All lines of a multi-line +@var{command-list} except the last line must be terminated with a +backslash (@samp{\}). Any commands are allowed, except for @samp{g}, +@samp{G}, @samp{v}, and @samp{V}. By default, a newline alone in +@var{command-list} is equivalent to a @samp{p} command. If @command{ed} +is invoked with the command-line option @samp{-G}, then a newline in +@var{command-list} is equivalent to a @samp{.+1p} command. + +@item (1,$)G /@var{re}/ +Interactive global command. Interactively edits the addressed lines +matching a regular expression @var{re}. For each matching line, the line +is printed, the current address is set, and the user is prompted to +enter a @var{command-list}. At the end of the @samp{G} command, the +current address is set to the last line affected by (the last) +@var{command-list}. + +The format of @var{command-list} is the same as that of the @samp{g} +command. A newline alone acts as a null command list. A single @samp{&} +repeats the last non-null command list. + +@item H +Toggles the printing of error explanations. By default, explanations are +not printed. It is recommended that ed scripts begin with this command +to aid in debugging. + +@item h +Prints an explanation of the last error. + +@item (.)i +Inserts text in the buffer before the current line. The address @samp{0} +(zero) is valid for this command; it is equivalent to address @samp{1}. +Text is entered in input mode. The current address is set to the last +line entered. + +@item (.,.+1)j +Joins the addressed lines. The addressed lines are deleted from the +buffer and replaced by a single line containing their joined text. The +current address is set to the resultant line. + +@item (.)kx +Marks a line with a lower case letter @samp{x}. The line can then be +addressed as @samp{'x} (i.e., a single quote followed by @samp{x}) in +subsequent commands. The mark is not cleared until the line is deleted +or otherwise modified. + +@item (.,.)l +Prints the addressed lines unambiguously. The end of each line is marked +with a @samp{$}, and every @samp{$} character within the text is printed +with a preceding backslash. The current address is set to the last line +printed. + +@item (.,.)m(.) +Moves lines in the buffer. The addressed lines are moved to after the +right-hand destination address, which may be the address @samp{0} +(zero). The current address is set to the new address of the last line +moved. + +@item (.,.)n +Prints the addressed lines, preceding each line by its line number and a +@key{tab}. The current address is set to the last line printed. + +@item (.,.)p +Prints the addressed lines. The current address is set to the last line +printed. + +@item P +Toggles the command prompt on and off. Unless a prompt is specified with +command-line option @samp{-p}, the command prompt is by default turned +off. + +@item q +Quits @command{ed}. + +@item Q +Quits @command{ed} unconditionally. This is similar to the @code{q} +command, except that unwritten changes are discarded without warning. + +@item ($)r @var{file} +Reads @var{file} to after the addressed line. If @var{file} is not +specified, then the default filename is used. If there is no default +filename prior to the command, then the default filename is set to +@var{file}. Otherwise, the default filename is unchanged. The current +address is set to the last line read. + +@item ($)r !@var{command} +Reads to after the addressed line the standard output of +@samp{!command}, (see the @samp{!} command below). The default filename +is unchanged. The current address is set to the last line read. + +@item (.,.)s /@var{re}/@var{replacement}/ +@itemx (.,.)s /@var{re}/@var{replacement}/g +@itemx (.,.)s /@var{re}/@var{replacement}/@var{n} +Replaces text in the addressed lines matching a regular expression +@var{re} with @var{replacement}. By default, only the first match in +each line is replaced. If the @samp{g} (global) suffix is given, then +every match is replaced. The @var{n} suffix, where @var{n} is a postive +number, causes only the @var{n}th match to be replaced. It is an error +if no substitutions are performed on any of the addressed lines. The +current address is set to the last line affected. + +@var{re} and @var{replacement} may be delimited by any character other +than @key{space}, @key{newline} and the characters used by the form of +the @samp{s} command shown below. If one or two of the last delimiters +is omitted, then the last line affected is printed as if the print +suffix @samp{p} were specified. + +An unescaped @samp{&} in @var{replacement} is replaced by the currently +matched text. The character sequence @samp{\@var{m}} where @var{m} is a +number in the range [1,9], is replaced by the @var{m}th backreference +expression of the matched text. If @var{replacement} consists of a +single @samp{%}, then @var{replacement} from the last substitution is +used. Newlines may be embedded in @var{replacement} if they are escaped +with a backslash (@samp{\}). + +@item (.,.)s +Repeats the last substitution. This form of the @samp{s} command accepts +a count suffix @var{n}, and any combination of the characters @samp{r}, +@samp{g}, and @samp{p}. If a count suffix @var{n} is given, then only +the @var{n}th match is replaced. The @samp{r} suffix causes the regular +expression of the last search to be used instead of the that of the last +substitution. The @samp{g} suffix toggles the global suffix of the last +substitution. The @samp{p} suffix toggles the print suffix of the last +substitution. The current address is set to the last line affected. + +@item (.,.)t(.) +Copies (i.e., transfers) the addressed lines to after the right-hand +destination address, which may be the address @samp{0} (zero). The +current address is set to the last line copied. + +@item u +Undoes the last command and restores the current address to what it was +before the command. The global commands @samp{g}, @samp{G}, @samp{v}, +and @samp{V} are treated as a single command by undo. @samp{u} is its +own inverse. + +@item (1,$)v /@var{re}/@var{command-list} +This is similar to the @samp{g} command except that it applies +@var{command-list} to each of the addressed lines not matching the +regular expression @var{re}. + +@item (1,$)V /@var{re}/ +This is similar to the @samp{G} command except that it interactively +edits the addressed lines not matching the regular expression @var{re}. + +@item (1,$)w @var{file} +Writes the addressed lines to @var{file}. Any previous contents of +@var{file} is lost without warning. If there is no default filename, +then the default filename is set to @var{file}, otherwise it is +unchanged. If no filename is specified, then the default filename is +used. The current address is unchanged. + +@item (1,$)w !@var{command} +Writes the addressed lines to the standard input of +@samp{!@var{command}}, (see the @samp{!} command below). The default +filename and current address are unchanged. + +@item (1,$)wq @var{file} +Writes the addressed lines to @var{file}, and then executes a @samp{q} +command. + +@item (1,$)W @var{file} +Appends the addressed lines to the end of @var{file}. This is similar to +the @samp{w} command, expect that the previous contents of file is not +clobbered. The current address is unchanged. + +@item (.)x +Copies (puts) the contents of the cut buffer to after the addressed +line. The current address is set to the last line copied. + +@item (.,.)y +Copies (yanks) the addressed lines to the cut buffer. The cut buffer is +overwritten by subsequent @samp{y}, @samp{s}, @samp{j}, @samp{d}, or +@samp{c} commands. The current address is unchanged. + +@item (.+1)z @var{n} +Scrolls @var{n} lines at a time starting at addressed line, and sets +window size to @var{n}. If @var{n} is not specified, then the current +window size is used. Window size defaults to screen size minus two +lines, or to 22 if screen size can't be determined. The current address +is set to the last line printed. + +@item !@var{command} +Executes @var{command} via @command{sh (1)}. If the first character of +@var{command} is @samp{!}, then it is replaced by text of the previous +@samp{!@var{command}}. @command{ed} does not process @var{command} for +backslash (@samp{\}) escapes. However, an unescaped @samp{%} is replaced +by the default filename. When the shell returns from execution, a +@samp{!} is printed to the standard output. The current line is +unchanged. + +@item (.,.)# +Begins a comment; the rest of the line, up to a newline, is ignored. If +a line address followed by a semicolon is given, then the current +address is set to that address. Otherwise, the current address is +unchanged. + +@item ($)= +Prints the line number of the addressed line. + +@item (.+1)@key{newline} +An address alone prints the addressed line. A @key{newline} alone is +equivalent to @samp{+1p}. the current address is set to the address of +the printed line. + +@end table + + +@node Limitations +@chapter Limitations + +If the terminal hangs up, @command{ed} attempts to write the buffer to +file @file{ed.hup} or, if this fails, to @file{$HOME/ed.hup}. + +@command{ed} processes @var{file} arguments for backslash escapes, i.e., +in a filename, any character preceded by a backslash (@samp{\}) is +interpreted literally. + +If a text (non-binary) file is not terminated by a newline character, +then @command{ed} appends one on reading/writing it. In the case of a +binary file, @command{ed} does not append a newline on reading/writing. + +Per line overhead: 2 @code{pointer}s, 1 @code{long int}, and 1 @code{int}. + + +@node Diagnostics +@chapter Diagnostics + +When an error occurs, if @command{ed}'s input is from a regular file or +here document, then it exits, otherwise it prints a @samp{?} and returns +to command mode. An explanation of the last error can be printed with +the @samp{h} (help) command. + +If the @samp{u} (undo) command occurs in a global command list, then the +command list is executed only once. + +Attempting to quit @command{ed} or edit another file before writing a +modified buffer results in an error. If the command is entered a second +time, it succeeds, but any changes to the buffer are lost. + +Exit status: 0 if no errors occurred; otherwise >0. + + +@node Problems +@chapter Reporting bugs + +There are probably bugs in @command{ed}. There are certainly errors and +omissions in this manual. If you report them, they will get fixed. If +you don't, no one will ever know about them and they will remain unfixed +for all eternity, if not longer. + +If you find a bug in @command{ed}, please send electronic mail to +@email{bug-ed@@gnu.org}. Include the version number, which you can +find by running @w{@code{ed --version}}. + + +@node GNU Free Documentation License +@chapter GNU Free Documentation License +@include fdl.texi + +@bye |