


ED(1)		    UNIX Programmer's Manual		    ED(1)



NAME
     ed - text editor

SYNOPSIS
     ed [ - ] [ name ]

DESCRIPTION
     _E_d is the standard text editor.

     If a _n_a_m_e argument is given, _e_d simulates an _e command (see
     below) on the named file; that is to say, the file is read
     into _e_d'_s buffer so that it can be edited.  The optional -
     suppresses the printing of explanatory output and should be
     used when the standard input is an editor script.

     _E_d operates on a copy of any file it is editing; changes
     made in the copy have no effect on the file until a _w
     (write) command is given.	The copy of the text being edited
     resides in a temporary file called the _b_u_f_f_e_r.

     Commands to _e_d have a simple and regular structure: zero or
     more _a_d_d_r_e_s_s_e_s followed by a single character _c_o_m_m_a_n_d, pos-
     sibly followed by parameters to the command.  These
     addresses specify one or more lines in the buffer.  Missing
     addresses are supplied by default.

     In general, only one command may appear on a line.  Certain
     commands allow the addition of text to the buffer.  While _e_d
     is accepting text, it is said to be in _i_n_p_u_t _m_o_d_e. In this
     mode, no commands are recognized; all input is merely col-
     lected.  Input mode is left by typing a period `.' alone at
     the beginning of a line.

     _E_d supports a limited form of _r_e_g_u_l_a_r _e_x_p_r_e_s_s_i_o_n notation.
     A regular expression specifies a set of strings of charac-
     ters.  A member of this set of strings is said to be _m_a_t_c_h_e_d
     by the regular expression.  In the following specification
     for regular expressions the word `character' means any char-
     acter but newline.

     1.   Any character except a special character matches
	  itself.  Special characters are the regular expression
	  delimiter plus \[.  and sometimes ^*$.

     2.   A . matches any character.

     3.   A \ followed by any character except a digit or ()
	  matches that character.

     4.   A nonempty string _s bracketed [_s] (or [^_s]) matches any
	  character in (or not in) _s. In _s, \ has no special
	  meaning, and ] may only appear as the first letter.  A



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	  substring _a-_b, with _a and _b in ascending ASCII order,
	  stands for the inclusive range of ASCII characters.

     5.   A regular expression of form 1-4 followed by * matches
	  a sequence of 0 or more matches of the regular expres-
	  sion.

     6.   A regular expression, _x, of form 1-8, bracketed \(_x\)
	  matches what _x matches.

     7.   A \ followed by a digit _n matches a copy of the string
	  that the bracketed regular expression beginning with
	  the _nth \( matched.

     8.   A regular expression of form 1-8, _x, followed by a reg-
	  ular expression of form 1-7, _y matches a match for _x
	  followed by a match for _y, with the _x match being as
	  long as possible while still permitting a _y match.

     9.   A regular expression of form 1-8 preceded by ^ (or fol-
	  lowed by $), is constrained to matches that begin at
	  the left (or end at the right) end of a line.

     10.  A regular expression of form 1-9 picks out the longest
	  among the leftmost matches in a line.

     11.  An empty regular expression stands for a copy of the
	  last regular expression encountered.

     Regular expressions are used in addresses to specify lines
     and in one command (see _s below) to specify a portion of a
     line which is to be replaced.  If it is desired to use one
     of the regular expression metacharacters as an ordinary
     character, that character may be preceded by `\'.	This also
     applies to the character bounding the regular expression
     (often `/') and to `\' itself.

     To understand addressing in _e_d it is necessary to know that
     at any time there is a _c_u_r_r_e_n_t _l_i_n_e. Generally speaking, the
     current line is the last line affected by a command; how-
     ever, the exact effect on the current line is discussed
     under the description of the command.  Addresses are con-
     structed as follows.

     1.   The character `.' addresses the current line.

     2.   The character `$' addresses the last line of the
	  buffer.

     3.   A decimal number _n addresses the _n-th line of the
	  buffer.




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     4.   `'_x' addresses the line marked with the name _x, which
	  must be a lower-case letter.	Lines are marked with the
	  _k command described below.

     5.   A regular expression enclosed in slashes `/' addresses
	  the line found by searching forward from the current
	  line and stopping at the first line containing a string
	  that matches the regular expression.	If necessary the
	  search wraps around to the beginning of the buffer.

     6.   A regular expression enclosed in queries `?' addresses
	  the line found by searching backward from the current
	  line and stopping at the first line containing a string
	  that matches the regular expression.	If necessary the
	  search wraps around to the end of the buffer.

     7.   An address followed by a plus sign `+' or a minus sign
	  `-' followed by a decimal number specifies that address
	  plus (resp. minus) the indicated number of lines.  The
	  plus sign may be omitted.

     8.   If an address begins with `+' or `-' the addition or
	  subtraction is taken with respect to the current line;
	  e.g. `-5' is understood to mean `.-5'.

     9.   If an address ends with `+' or `-', then 1 is added
	  (resp. subtracted).  As a consequence of this rule and
	  rule 8, the address `-' refers to the line before the
	  current line.  Moreover, trailing `+' and `-' charac-
	  ters have cumulative effect, so `--' refers to the
	  current line less 2.

     10.  To maintain compatibility with earlier versions of the
	  editor, the character `^' in addresses is equivalent to
	  `-'.

     Commands may require zero, one, or two addresses.	Commands
     which require no addresses regard the presence of an address
     as an error.  Commands which accept one or two addresses
     assume default addresses when insufficient are given.  If
     more addresses are given than such a command requires, the
     last one or two (depending on what is accepted) are used.

     Addresses are separated from each other typically by a comma
     `,'.  They may also be separated by a semicolon `;'.  In
     this case the current line `.' is set to the previous
     address before the next address is interpreted.  This
     feature can be used to determine the starting line for for-
     ward and backward searches (`/', `?').  The second address
     of any two-address sequence must correspond to a line fol-
     lowing the line corresponding to the first address.  The
     special form `%' is an abbreviation for the address pair



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     `1,$'.

     In the following list of _e_d commands, the default addresses
     are shown in parentheses.	The parentheses are not part of
     the address, but are used to show that the given addresses
     are the default.

     As mentioned, it is generally illegal for more than one com-
     mand to appear on a line.	However, most commands may be
     suffixed by `p' or by `l', in which case the current line is
     either printed or listed respectively in the way discussed
     below.  Commands may also be suffixed by `n', meaning the
     output of the command is to be line numbered.  These suf-
     fixes may be combined in any order.

     (.)a
     <text>
     .
	  The append command reads the given text and appends it
	  after the addressed line.  `.' is left on the last line
	  input, if there were any, otherwise at the addressed
	  line.  Address `0' is legal for this command; text is
	  placed at the beginning of the buffer.

     (., .)c
     <text>
     .
	  The change command deletes the addressed lines, then
	  accepts input text which replaces these lines.  `.' is
	  left at the last line input; if there were none, it is
	  left at the line preceding the deleted lines.

     (., .)d
	  The delete command deletes the addressed lines from the
	  buffer.  The line originally after the last line
	  deleted becomes the current line; if the lines deleted
	  were originally at the end, the new last line becomes
	  the current line.

     e filename
	  The edit command causes the entire contents of the
	  buffer to be deleted, and then the named file to be
	  read in.  `.' is set to the last line of the buffer.
	  The number of characters read is typed.  `filename' is
	  remembered for possible use as a default file name in a
	  subsequent _r or _w command.  If `filename' is missing,
	  the remembered name is used.

     E filename
	  This command is the same as _e, except that no diagnos-
	  tic results when no _w has been given since the last
	  buffer alteration.



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     f filename
	  The filename command prints the currently remembered
	  file name.  If `filename' is given, the currently
	  remembered file name is changed to `filename'.

     (1,$)g/regular expression/command list
	  In the global command, the first step is to mark every
	  line which matches the given regular expression.  Then
	  for every such line, the given command list is executed
	  with `.' initially set to that line.	A single command
	  or the first of multiple commands appears on the same
	  line with the global command.  All lines of a multi-
	  line list except the last line must be ended with `\'.
	  _A, _i, and _c commands and associated input are permit-
	  ted; the `.' terminating input mode may be omitted if
	  it would be on the last line of the command list.  The
	  commands _g and _v are not permitted in the command list.

     (.)i

     <text>
     .
	  This command inserts the given text before the
	  addressed line.  `.' is left at the last line input,
	  or, if there were none, at the line before the
	  addressed line.  This command differs from the _a com-
	  mand only in the placement of the text.

     (., .+1)j
	  This command joins the addressed lines into a single
	  line; intermediate newlines simply disappear.  `.' is
	  left at the resulting line.

     ( . )k_x
	  The mark command marks the addressed line with name _x,
	  which must be a lower-case letter.  The address form
	  `'_x' then addresses this line.

     (., .)l
	  The list command prints the addressed lines in an unam-
	  biguous way: non-graphic characters are printed in
	  two-digit octal, and long lines are folded.  The _l com-
	  mand may be placed on the same line after any non-i/o
	  command.

     (., .)m_a
	  The move command repositions the addressed lines after
	  the line addressed by _a.  The last of the moved lines
	  becomes the current line.

     (., .)p
	  The print command prints the addressed lines.  `.' is



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	  left at the last line printed.  The _p command may be
	  placed on the same line after any non-i/o command.

     (., .)P
	  This command is a synonym for _p.

     q	  The quit command causes _e_d to exit.  No automatic write
	  of a file is done.

     Q	  This command is the same as _q, except that no diagnos-
	  tic results when no _w has been given since the last
	  buffer alteration.

     ($)r filename
	  The read command reads in the given file after the
	  addressed line.  If no file name is given, the remem-
	  bered file name, if any, is used (see _e and _f com-
	  mands).  The file name is remembered if there was no
	  remembered file name already.  Address `0' is legal for
	  _r and causes the file to be read at the beginning of
	  the buffer.  If the read is successful, the number of
	  characters read is typed.  `.' is left at the last line
	  read in from the file.

     ( ., .)s/regular expression/replacement/	    or,
     ( ., .)s/regular expression/replacement/g
	  The substitute command searches each addressed line for
	  an occurrence of the specified regular expression.  On
	  each line in which a match is found, all matched
	  strings are replaced by the replacement specified, if
	  the global replacement indicator `g' appears after the
	  command.  If the global indicator does not appear, only
	  the first occurrence of the matched string is replaced.
	  It is an error for the substitution to fail on all
	  addressed lines.  Any punctuation character may be used
	  instead of `/' to delimit the regular expression and
	  the replacement.  `.' is left at the last line substi-
	  tuted.

	  An ampersand `&' appearing in the replacement is
	  replaced by the string matching the regular expression.
	  The special meaning of `&' in this context may be
	  suppressed by preceding it by `\'.  The characters `_\_n'
	  where _n is a digit, are replaced by the text matched by
	  the _n-th regular subexpression enclosed between `\('
	  and `\)'.  When nested, parenthesized subexpressions
	  are present, _n is determined by counting occurrences of
	  `\(' starting from the left.

	  Lines may be split by substituting new-line characters
	  into them.  The new-line in the replacement string must
	  be escaped by preceding it by `\'.



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	  One or two trailing delimiters may be omitted, implying
	  the `p' suffix.  The special form `s' followed by _n_o
	  delimiters repeats the most recent substitute command
	  on the addressed lines.  The `s' may be followed by the
	  letters r (use the most recent regular expression for
	  the left hand side, instead of the most recent left
	  hand side of a substitute command), p (complement the
	  setting of the _p suffix from the previous substitu-
	  tion), or g (complement the setting of the _g suffix).
	  These letters may be combined in any order.

     (., .)t_a
	  This command acts just like the _m command, except that
	  a copy of the addressed lines is placed after address _a
	  (which may be 0).  `.' is left on the last line of the
	  copy.

     (., .)u
	  The undo command restores the buffer to it's state
	  before the most recent buffer modifying command.  The
	  current line is also restored.  Buffer modifying com-
	  mands are _a, _c, _d, _g, _i, _k, and _v. For purposes of
	  undo, _g and _v are considered to be a single buffer
	  modifying command.  Undo is its own inverse.

	  When _e_d runs out of memory (at about 8000 lines on any
	  16 bit mini-computer such as the PDP-11) This full undo
	  is not possible, and _u can only undo the effect of the
	  most recent substitute on the current line.  This res-
	  tricted undo also applies to editor scripts when _e_d is
	  invoked with the - option.

     (1, $)v/regular expression/command list
	  This command is the same as the global command _g except
	  that the command list is executed _g with `.' initially
	  set to every line _e_x_c_e_p_t those matching the regular
	  expression.

     (1, $)w filename
	  The write command writes the addressed lines onto the
	  given file.  If the file does not exist, it is created.
	  The file name is remembered if there was no remembered
	  file name already.  If no file name is given, the
	  remembered file name, if any, is used (see _e and _f com-
	  mands).  `.' is unchanged.  If the command is success-
	  ful, the number of characters written is printed.

     (1, $)W filename
	  This command is the same as _w, except that the
	  addressed lines are appended to the file.

     (1, $)wq filename



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	  This command is the same as _w except that afterwards a
	  _q command is done, exiting the editor after the file is
	  written.

     (.+1)z    or,
     (.+1)z_n
	  This command scrolls through the buffer starting at the
	  addressed line.  22 (or _n, if given) lines are printed.
	  The last line printed becomes the current line.  The
	  value _n is sticky, in that it becomes the default for
	  future _z commands.

     ($)= The line number of the addressed line is typed.  `.' is
	  unchanged by this command.

     !<shell command>
	  The remainder of the line after the `!' is sent to
	  _s_h(1) to be interpreted as a command.  `.' is
	  unchanged.

     (.+1,.+1)<newline>
	  An address alone on a line causes the addressed line to
	  be printed.  A blank line alone is equivalent to
	  `.+1p'; it is useful for stepping through text.  If two
	  addresses are present with no intervening semicolon, _e_d
	  prints the range of lines.  If they are separated by a
	  semicolon, the second line is printed.

     If an interrupt signal (ASCII DEL) is sent, _e_d prints
     `?interrupted' and returns to its command level.

     Some size limitations: 512 characters per line, 256 charac-
     ters per global command list, 64 characters per file name,
     and, on mini computers, 128K characters in the temporary
     file.  The limit on the number of lines depends on the
     amount of core: each line takes 2 words.

     When reading a file, _e_d discards ASCII NUL characters and
     all characters after the last newline.  It refuses to read
     files containing non-ASCII characters.

FILES
     /tmp/e*
     edhup: work is saved here if terminal hangs up

SEE ALSO
     B. W. Kernighan, _A _T_u_t_o_r_i_a_l _I_n_t_r_o_d_u_c_t_i_o_n _t_o _t_h_e _E_D _T_e_x_t _E_d_i_-
     _t_o_r
     B. W. Kernighan, _A_d_v_a_n_c_e_d _e_d_i_t_i_n_g _o_n _U_N_I_X
     ex(1), sed(1), crypt(1)





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DIAGNOSTICS
     `?name' for inaccessible file; `?self-explanatory message'
     for other errors.

     To protect against throwing away valuable work, a _q or _e
     command is considered to be in error, unless a _w has
     occurred since the last buffer change.  A second _q or _e will
     be obeyed regardless.

BUGS
     The _l command mishandles DEL.
     The _u_n_d_o command causes marks to be lost on affected lines.











































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