ED(1)                                                       ED(1)

     NAME
          ed - text editor

     SYNOPSIS
          ed [ - ] [ -x ] [ name ]

     DESCRIPTION
          Ed is the standard text editor.

          If a name argument is given, ed simulates an e command (see
          below) on the named file; that is to say, the file is read
          into ed's buffer so that it can be edited.  If -x is pre-
          sent, an x command is simulated first to handle an encrypted
          file.  The optional - suppresses the printing of character
          counts by e, r, and w commands.

          Ed 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 buffer.

          Commands to ed have a simple and regular structure: zero or
          more addresses followed by a single character command, 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 ed
          is accepting text, it is said to be in input mode. 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.

          Ed supports a limited form of regular expression notation.
          A regular expression specifies a set of strings of charac-
          ters.  A member of this set of strings is said to be matched
          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.

     ED(1)                                                       ED(1)

          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
               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 ed it is necessary to know that
          at any time there is a current line. 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.

     ED(1)                                                       ED(1)

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

          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 cur-
               rent 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 fea-
          ture can be used to determine the starting line for forward
          and backward searches (`/', `?').  The second address of any

     ED(1)                                                       ED(1)

          two-address sequence must correspond to a line following the
          line corresponding to the first address.

          In the following list of ed 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.

          (.)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.

     ED(1)                                                       ED(1)

          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.

          ( . )kx
               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.

          (., .)ma
               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

     ED(1)                                                       ED(1)

               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 ed 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 character other than space or
               new-line may be used instead of `/' to delimit the reg-
               ular expression and the replacement.  `.' is left at
               the last line substituted.

               An ampersand `&' appearing in the replacement is
               replaced by the string matching the regular expression.
               The special meaning of `&' in this context may be sup-
               pressed 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 `\'.

     ED(1)                                                       ED(1)

          (., .)ta
               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 preceding contents of the
               current line, which must be the last line in which a
               substitution was made.

          (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 except 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
               mode 666 (readable and writable by everyone).  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 commands).  `.' is
               unchanged.  If the command is successful, 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.

          x    A key string is demanded from the standard input.
               Later r, e and w commands will encrypt and decrypt the
               text with this key by the algorithm of crypt(1). An
               explicitly empty key turns off encryption.

          ($)= 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
               sh(1) to be interpreted as a command.  `.'  is
               unchanged.

          (.+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 an interrupt signal (ASCII DEL) is sent, ed prints a `?'
          and returns to its command level.

     ED(1)                                                       ED(1)

          Some size limitations: 512 characters per line, 256 charac-
          ters per global command list, 64 characters per file name,
          and 128K characters in the temporary file.  The limit on the
          number of lines depends on the amount of core: each line
          takes 1 word.

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

     FILES
          /tmp/e*
          ed.hup: work is saved here if terminal hangs up

     SEE ALSO
          B. W. Kernighan, A Tutorial Introduction to the ED Text Edi-
          tor
          B. W. Kernighan, Advanced editing on UNIX
          sed(1), crypt(1)

     DIAGNOSTICS
          `?name' for inaccessible file; `?' for errors in commands;
          `?TMP' for temporary file overflow.

          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.
          A ! command cannot be subject to a g command.
          Because 0 is an illegal address for a w command, it is not
          possible to create an empty file with ed.