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red(1)

NAME

     ed, red -- text editor

SYNOPSIS

     ed [-] [-sx] [-p string] [file]
     red [-] [-sx] [-p string] [file]

DESCRIPTION

     The ed utility is a line-oriented text editor.  It is used to create,
     display, modify and otherwise manipulate text files.  When invoked as
     red, the editor runs in "restricted" mode, in which the only difference
     is that the editor restricts the use of filenames which start with `!'
     (interpreted as shell commands by ed) or contain a `/'.  Note that edit-
     ing outside of the current directory is only prohibited if the user does
     not have write access to the current directory.  If a user has write
     access to the current directory, then symbolic links can be created in
     the current directory, in which case red will not stop the user from
     editing the file that the symbolic link points to.

     If invoked with a file argument, then a copy of file is read into the
     editor's buffer.  Changes are made to this copy and not directly to file
     itself.  Upon quitting ed, any changes not explicitly saved with a w com-
     mand are lost.

     Editing is done in two distinct modes: command and input.	When first
     invoked, 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:

     ,s/old/new/g

     which replaces all occurrences of the string old with new.

     When an input command, such as a (append), i (insert) or c (change), is
     given, 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.  Lines consist of text up
     to and including a newline character.  Input mode is terminated by enter-
     ing a single period (.) on a line.

     All ed commands operate on whole lines or ranges of lines; e.g., the d
     command deletes lines; the m command moves lines, and so on.  It is pos-
     sible to modify only a portion of a line by means of replacement, as in
     the example above.  However even here, the s command is applied to whole
     lines at a time.

     In general, 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:

     [address[,address]]command[parameters]

     The 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.

OPTIONS

     -p string
	     Specify a command prompt.	This may be toggled on and off with
	     the P command.

     file    Specify the name of a file to read.  If 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 file executed via
	     sh(1).  To read a file whose name begins with a bang, prefix the
	     name with a backslash (\).  The default filename is set to file
	     only if it is not prefixed with a bang.

LINE ADDRESSING

     An address represents the number of a line in the buffer.	The ed utility
     maintains a 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.

     A line address is constructed from one of the bases in the list below,
     optionally followed by a numeric offset.  The offset may include any com-
     bination of digits, operators (i.e., +, - and ^) and whitespace.
     Addresses are read from left to right, and their values are computed rel-
     ative to the current address.

     One exception to the rule that addresses represent line numbers is the
     address 0 (zero).	This means "before the first line," and is legal wher-
     ever it makes sense.

     An address range is two addresses separated either by a comma or semi-
     colon.  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 n-tuple of addresses is given
     where n > 2, then the corresponding range is determined by the last two
     addresses in the n-tuple.	If only one address is expected, then the last
     address is used.

     Each address in a comma-delimited range is interpreted relative to the
     current address.  In a semi-colon-delimited range, the first address is
     used to set the current address, and the second address is interpreted
     relative to the first.

     The following address symbols are recognized:

     .	     The current line (address) in the buffer.

     $	     The last line in the buffer.

     n	     The nth, line in the buffer where n is a number in the range
	     [0,$].

     - or ^  The previous line.  This is equivalent to -1 and may be repeated
	     with cumulative effect.

     -n or ^n
	     The nth previous line, where n is a non-negative number.

     +	     The next line.  This is equivalent to +1 and may be repeated with
	     cumulative effect.

     /re/    The next line containing the regular expression re.  The search
	     wraps to the beginning of the buffer and continues down to the
	     current line, if necessary.  // repeats the last search.

     ?re?    The previous line containing the regular expression re.  The
	     search wraps to the end of the buffer and continues up to the
	     current line, if necessary.  ?? repeats the last search.

     'lc     The line previously marked by a k (mark) command, where lc is a
	     lower case letter.

REGULAR EXPRESSIONS

     Regular expressions are patterns used in selecting text.  For example,
     the command:

     g/string/

     prints all lines containing string.  Regular expressions are also used by
     the s command for selecting old text to be replaced with new.

     In addition to a specifying string literals, regular expressions can rep-
     resent 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:

     c	     Any character c not listed below, including `{', `}', `(', `)',
	     `<' and `>', matches itself.

     \c      Any backslash-escaped character c, except for `{', `}', `(', `)',
	     `<' and `>', matches itself.

     .	     Match any single character.

     [char-class]
	     Match any single character in char-class.	To include a `]' in
	     char-class, it must be the first character.  A range of charac-
	     ters may be specified by separating the end characters of the
	     range with a `-', e.g., `a-z' specifies the lower case charac-
	     ters.  The following literal expressions can also be used in
	     char-class to specify sets of characters:

	     [:alnum:]	  [:cntrl:]    [:lower:]    [:space:]
	     [:alpha:]	  [:digit:]    [:print:]    [:upper:]
	     [:blank:]	  [:graph:]    [:punct:]    [:xdigit:]

	     If `-' appears as the first or last character of char-class, then
	     it matches itself.  All other characters in char-class match
	     themselves.

	     Patterns in char-class of the form:

	       [.col-elm.] or,
	       [=col-elm=]

     ^	     If ^ is the first character of a regular expression, then it
	     anchors the regular expression to the beginning of a line.  Oth-
	     erwise, it matches itself.

     $	     If $ is the last character of a regular expression, it anchors
	     the regular expression to the end of a line.  Otherwise, it
	     matches itself.

     \<      Anchor the single character regular expression or subexpression
	     immediately following it to the beginning of a word.  (This may
	     not be available)

     \>      Anchor the single character regular expression or subexpression
	     immediately following it to the end of a word.  (This may not be
	     available)

     \(re\)  Define a subexpression re.  Subexpressions may be nested.	A sub-
	     sequent backreference of the form \n, where n is a number in the
	     range [1,9], expands to the text matched by the nth subexpres-
	     sion.  For example, the regular expression `\(.*\)\1' matches any
	     string consisting of identical adjacent substrings.  Subexpres-
	     sions are ordered relative to their left delimiter.

     *	     Match the single character regular expression or subexpression
	     immediately preceding it zero or more times.  If * is the first
	     character of a regular expression or subexpression, then it
	     matches itself.  The * operator sometimes yields unexpected
	     results.  For example, the regular expression `b*' matches the
	     beginning of the string `abbb' (as opposed to the substring
	     `bbb'), since a null match is the only left-most match.

     \{n,m\} or \{n,\} or \{n\}
	     Match the single character regular expression or subexpression
	     immediately preceding it at least n and at most m times.  If m is
	     omitted, then it matches at least n times.  If the comma is also
	     omitted, then it matches exactly n times.

     Additional regular expression operators may be defined depending on the
     particular regex(3) implementation.

COMMANDS

     All ed commands are single characters, though some require additional
     parameters.  If a command's parameters extend over several lines, then
     each line except for the last must be terminated with a backslash (\).

     In general, at most one command is allowed per line.  However, most com-
     mands accept a print suffix, which is any of p (print), l (list), or n
     (enumerate), to print the last line affected by the command.

     An interrupt (typically ^C) has the effect of aborting the current com-
     mand and returning the editor to command mode.

     The ed utility recognizes the following commands.	The commands are shown
     together with the default address or address range supplied if none is
     specified (in parenthesis).

     (.)a    Append text to the buffer after the addressed line.  Text is
	     entered in input mode.  The current address is set to last line
	     line.  Otherwise the current address is set to the line before
	     the deleted range.

     e file  Edit file, and sets the default filename.	If file is not speci-
	     fied, 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.

     e !command
	     Edit the standard output of !command, (see !command below).  The
	     default filename is unchanged.  Any lines in the buffer are
	     deleted before the output of command is read.  The current
	     address is set to the last line read.

     E file  Edit file unconditionally.  This is similar to the e command,
	     except that unwritten changes are discarded without warning.  The
	     current address is set to the last line read.

     f file  Set the default filename to file.	If file is not specified, then
	     the default unescaped filename is printed.

     (1,$)g/re/command-list
	     Apply command-list to each of the addressed lines matching a reg-
	     ular expression re.  The current address is set to the line cur-
	     rently matched before command-list is executed.  At the end of
	     the g command, the current address is set to the last line
	     affected by command-list.

	     Each command in command-list must be on a separate line, and
	     every line except for the last must be terminated by a backslash
	     (\).  Any commands are allowed, except for g, G, v, and V.  A
	     newline alone in command-list is equivalent to a p command.

     (1,$)G/re/
	     Interactively edit the addressed lines matching a regular expres-
	     sion re.  For each matching line, the line is printed, the cur-
	     rent address is set, and the user is prompted to enter a
	     command-list.  At the end of the G command, the current address
	     is set to the last line affected by (the last) command-list.

	     The format of command-list is the same as that of the g command.
	     A newline alone acts as a null command list.  A single `&'
	     repeats the last non-null command list.

     H	     Toggle the printing of error explanations.  By default, explana-
	     tions are not printed.  It is recommended that ed scripts begin
	     with this command to aid in debugging.

     h	     Print an explanation of the last error.

     (.)i    Insert text in the buffer before the current line.  Text is
	     entered in input mode.  The current address is set to the last
	     line entered.

     (.,.+1)j
	     Join 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.
	     file, for instance), a ``--More--'' prompt is printed on the last
	     line.  The ed utility waits until the RETURN key is pressed
	     before displaying the next screen.  The current address is set to
	     the last line printed.

     (.,.)m(.)
	     Move lines in the buffer.	The addressed lines are moved to after
	     the right-hand destination address, which may be the address 0
	     (zero).  The current address is set to the last line moved.

     (.,.)n  Print the addressed lines along with their line numbers.  The
	     current address is set to the last line printed.

     (.,.)p  Print the addressed lines.  The current address is set to the
	     last line printed.

     P	     Toggle the command prompt on and off.  Unless a prompt was speci-
	     fied by with command-line option -p string, the command prompt is
	     by default turned off.

     q	     Quit ed.

     Q	     Quit ed unconditionally.  This is similar to the q command,
	     except that unwritten changes are discarded without warning.

     ($)r file
	     Read file to after the addressed line.  If file is not specified,
	     then the default filename is used.  If there was no default file-
	     name prior to the command, then the default filename is set to
	     file.  Otherwise, the default filename is unchanged.  The current
	     address is set to the last line read.

     ($)r !command
	     Read to after the addressed line the standard output of !command,
	     (see the !command below).	The default filename is unchanged.
	     The current address is set to the last line read.

     (.,.)s/re/replacement/

     (.,.)s/re/replacement/g

     (.,.)s/re/replacement/n
	     Replace text in the addressed lines matching a regular expression
	     re with replacement.  By default, only the first match in each
	     line is replaced.	If the g (global) suffix is given, then every
	     match to be replaced.  The n suffix, where n is a positive num-
	     ber, causes only the nth match to be replaced.  It is an error if
	     no substitutions are performed on any of the addressed lines.
	     The current address is set the last line affected.

	     Re and replacement may be delimited by any character other than
	     space and newline (see the s command below).  If one or two of
	     the last delimiters is omitted, then the last line affected is
	     printed as though the print suffix p were specified.

	     An unescaped `&' in replacement is replaced by the currently
	     matched text.  The character sequence \m, where m is a number in
	     the range [1,9], is replaced by the m th backreference expression
	     replaced.	The r suffix causes the regular expression of the last
	     search to be used instead of the that of the last substitution.
	     The g suffix toggles the global suffix of the last substitution.
	     The p suffix toggles the print suffix of the last substitution
	     The current address is set to the last line affected.

     (.,.)t(.)
	     Copy (i.e., transfer) the addressed lines to after the right-hand
	     destination address, which may be the address 0 (zero).  The cur-
	     rent address is set to the last line copied.

     u	     Undo the last command and restores the current address to what it
	     was before the command.  The global commands g, G, v, and V.  are
	     treated as a single command by undo.  u is its own inverse.

     (1,$)v/re/command-list
	     Apply command-list to each of the addressed lines not matching a
	     regular expression re.  This is similar to the g command.

     (1,$)V/re/
	     Interactively edit the addressed lines not matching a regular
	     expression re.  This is similar to the G command.

     (1,$)w file
	     Write the addressed lines to file.  Any previous contents of file
	     is lost without warning.  If there is no default filename, then
	     the default filename is set to file, otherwise it is unchanged.
	     If no filename is specified, then the default filename is used.
	     The current address is unchanged.

     (1,$)wq file
	     Write the addressed lines to file, and then executes a q command.

     (1,$)w !command
	     Write the addressed lines to the standard input of !command, (see
	     the !command below).  The default filename and current address
	     are unchanged.

     (1,$)W file
	     Append the addressed lines to the end of file.  This is similar
	     to the w command, expect that the previous contents of file is
	     not clobbered.  The current address is unchanged.

     x	     Prompt for an encryption key which is used in subsequent reads
	     and writes.  If a newline alone is entered as the key, then
	     encryption is turned off.	Otherwise, echoing is disabled while a
	     key is read.  Encryption/decryption is done using the bdes(1)
	     algorithm.

     (.+1)zn
	     Scroll n lines at a time starting at addressed line.  If n is not
	     specified, then the current window size is used.  The current
	     address is set to the last line printed.

     !command
	     Execute command via sh(1).  If the first character of command is
	     `!', then it is replaced by text of the previous !command.  The
	     ed utility does not process command for backslash (\) escapes.
	     line.

FILES

     /tmp/ed.*	buffer file
     ed.hup	the file to which ed attempts to write the buffer if the ter-
		minal hangs up

SEE ALSO

     bdes(1), sed(1), sh(1), vi(1), regex(3)

     USD:12-13

     B. W. Kernighan and P. J. Plauger, Software Tools in Pascal, 1981,
     Addison-Wesley.

LIMITATIONS

     The ed utility processes file arguments for backslash escapes, i.e., in a
     filename, any characters preceded by a backslash (\) are interpreted lit-
     erally.

     If a text (non-binary) file is not terminated by a newline character,
     then ed appends one on reading/writing it.  In the case of a binary file,
     ed does not append a newline on reading/writing.

     per line overhead: 4 ints

DIAGNOSTICS

     When an error occurs, ed prints a `?' and either returns to command mode
     or exits if its input is from a script.  An explanation of the last error
     can be printed with the h (help) command.

     Since the g (global) command masks any errors from failed searches and
     substitutions, it can be used to perform conditional operations in
     scripts; e.g.,

     g/old/s//new/

     replaces any occurrences of old with new.	If the u (undo) command occurs
     in a global command list, then the command list is executed only once.

     If diagnostics are not disabled, attempting to quit ed or edit another
     file before writing a modified buffer results in an error.  If the com-
     mand is entered a second time, it succeeds, but any changes to the buffer
     are lost.

HISTORY

     An ed command appeared in Version 1 AT&T UNIX.

BUGS

     The ed utility does not recognize multibyte characters.

FreeBSD 5.4			 July 3, 2004			   FreeBSD 5.4

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