ED(1)                                                       ED(1)

     NAME
          ed - text editor

     SYNOPSIS
          ed [ - ] [ -o ] [ file ]

     DESCRIPTION
          Ed is the standard text editor.

          If a file argument is given, ed simulates an `e' command
          (see below) on that file: it is read into ed's buffer so
          that it can be edited.  The options are

          -    Suppress the printing of character counts by `e', `r',
               and `w' commands and of the confirming `!'  by `!'
               commands.

          -o   (for output piping) Write all output to the standard
               error file except writing by `w' commands.  If no file
               is given, make /fd/1 the remembered file; see the `e'
               command below.

          Ed operates on a `buffer', a copy of the file it is editing;
          changes made in the buffer 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,
          one, or two addresses followed by a single character
          command, possibly 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 the regular expression notation described in
          regexp(6). 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

     ED(1)                                                       ED(1)

          at any time there is a current line. Generally, the current
          line is the last line affected by a command; however, the
          exact effect on the current line is discussed under the
          description of each command.  Addresses are constructed as
          follows.

          1.   The character `.', customarily called `dot', 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.

          4.   'x addresses the line marked with the name x, which
               must be a lower-case letter.  Lines are marked with the
               `k' command.

          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 nec-
               essary 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.   An address followed by `+' (or `-') followed by a regu-
               lar expression enclosed in slashes specifies the first
               matching line following (or preceding) that address.
               The search wraps around if necessary.  The `+' may be
               omitted, so `0/x/' addresses the first line in the
               buffer with an `x'.  Enclosing the regular expression
               in `?'  reverses the search direction.

          9.   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'.

          10.  If an address ends with `+' or `-', then 1 is added
               (resp. subtracted).  As a consequence of this rule and
               rule 9, the address `-' refers to the line before the

     ED(1)                                                       ED(1)

               current line.  Moreover, trailing `+' and `-' charac-
               ters have cumulative effect, so `--' refers to the cur-
               rent line less 2.

          11.  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 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.  If no address pre-
          cedes a comma or semicolon, line 1 is assumed; if no address
          follows, the last line of the buffer is assumed.  The second
          address of any 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.  `Dot' means the current line.

          (.)a
          <text>
          .    Read the given text and append it after the addressed
               line.  Dot 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 begin-
               ning of the buffer.

          (.,.)b[+-][pagesize][pln]
               Browse.  Print a `page', normally 20 lines.  The
               optional `+' (default) or `-' specifies whether the
               next or previous page is to be printed.  The optional
               pagesize is the number of lines in a page.  The
               optional `p', `n', or `l' causes printing in the speci-
               fied format, initially `p'.  Pagesize and format are
               remembered between `b' commands.  Dot is left at the
               last line displayed.

          (.,.)c
          <text>
          .    Change.  Delete the addressed lines, then accept input
               text to replace these lines.  Dot is left at the last
               line input; if there were none, it is left at the line

     ED(1)                                                       ED(1)

               preceding the deleted lines.

          (.,.)d
               Delete the addressed lines from the buffer.  Dot is set
               to the line following the last line deleted, or to the
               last line of the buffer if the deleted lines had no
               successor.

          e filename
               Edit.  Delete the entire contents of the buffer; then
               read the named file into the buffer.  Dot is set to the
               last line of the buffer.  The number of characters read
               is typed.  The file name is remembered for possible use
               in later `e', `r', or `w' commands.  If filename is
               missing, the remembered name is used.

          E filename
               Unconditional `e'; see ``q'' below.

          f filename
               Print the currently remembered file name.  If filename
               is given, the currently remembered file name is first
               changed to filename.

          (1,$)g/regular expression/command list
          (1,$)g/regular expression/
          (1,$)g/regular expression
               Global.  First mark every line which matches the given
               regularexpression.  Then for every such line, execute
               the command list with dot 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
               end with `\'.  The `.' terminating input mode for an
               `a', `i', `c' command 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.  Any
               character other than space or newline may be used
               instead of `/' to delimit the regular expression.  The
               second and third forms mean g/regular expression/p.

          (.)i
          <text>
          .    Insert the given text before the addressed line.  Dot
               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 command only in the placement of the
               text.

          (.,.+1)j
               Join the addressed lines into a single line; intermedi-
               ate newlines are deleted.  Dot is left at the resulting

     ED(1)                                                       ED(1)

               line.

          (.)kx
               Mark the addressed line with name x, which must be a
               lower-case letter.  The address form 'x then addresses
               this line.

          (.,.)l
               List.  Print the addressed lines in an unambiguous way:
               a tab is printed as `\t', a backspace as `\b', back-
               slashes as `\\', and non-printing characters as a back-
               slash, an `x', and four hexadecimal digits.  Long lines
               are folded, with the second and subsequent sub-lines
               indented one tab stop.  If the last character in the
               line is a blank, it is followed by `\n'.  An `l' may be
               appended, like `p', to any non-I/O command.

          (.,.)ma
               Move.  Reposition the addressed lines after the line
               addressed by a. Dot is left at the last moved line.

          (.,.)n
               Number.  Perform `p', prefixing each line with its line
               number and a tab.  An `n' may be appended, like `p', to
               any non-I/O command.

          (.,.)p
               Print the addressed lines.  Dot is left at the last
               line printed.  A `p' appended to any non-I/O command
               causes the then current line to be printed after the
               command is executed.

          (.,.)P
               This command is a synonym for `p'.

          q    Quit the editor.  No automatic write of a file is done.
               A `q' or `e' command is considered to be in error if
               the buffer has been modified since the last `w', `q',
               or `e' command.

          Q    Quit unconditionally.

          ($)r filename
               Read in the given file after the addressed line.  If no
               filename is given, the remembered file name is used.
               The file name is remembered if there were no remembered
               file name already.  If the read is successful, the num-
               ber of characters read is printed.  Dot is left at the
               last line read from the file.

          (.,.)sn/regular expression/replacement/
          (.,.)sn/regular expression/replacement/g

     ED(1)                                                       ED(1)

          (.,.)sn/regular expression/replacement
               Substitute.  Search each addressed line for an occur-
               rence of the specified regular expression.  On each
               line in which n matches are found (n defaults to 1 if
               missing), the nth matched string is replaced by the
               replacement specified.  If the global replacement indi-
               cator `g' appears after the command, all subsequent
               matches on the line are also replaced.  It is an error
               for the substitution to fail on all addressed lines.
               Any character other than space or newline may be used
               instead of `/' to delimit the regular expression and
               the replacement.  Dot is left at the last line substi-
               tuted.  The third form means
               sn/regular expression/replacement/p.  The second `/'
               may be omitted if the replacement is empty.

               An ampersand `&' appearing in the replacement is
               replaced by the string matching the regular expression.
               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 parenthe-
               sized subexpressions are present, n is determined by
               counting occurrences of `(' starting from the left.

               A literal `&', `/', `\' or newline may be included in a
               replacement by prefixing it with `\'.

          (.,.)ta
               Transfer.  Copy the addressed lines after the line
               addressed by a. Dot is left at the last line of the
               copy.

          (.,.)u
               Undo.  Restore the preceding contents of the first
               addressed line (sic), which must be the last line in
               which a substitution was made (double sic).

          (1,$)v/regular expression/command list
               This command is the same as the global command `g'
               except that the command list is executed with dot ini-
               tially set to every line except those matching the reg-
               ular expression.

          (1,$)w filename
               Write the addressed lines to the given file.  If the
               file does not exist, it is created with mode 666 (read-
               able and writable by everyone).  If no filename is
               given, the remembered file name, if any, is used.  The
               file name is remembered if there were no remembered
               file name already.  Dot is unchanged.  If the write is
               successful, the number of characters written is
               printed.

     ED(1)                                                       ED(1)

          (1,$)W filename
               Perform `w', but append to, instead of overwriting, any
               existing file contents.

          ($)= Print the line number of the addressed line.  Dot is
               unchanged.

          !shell command
               Send the remainder of the line after the `!'  to rc(1)
               to be interpreted as a command.  Dot is unchanged.

          (.+1)<newline>
               An address without a command is taken as a `p' command.
               A terminal `/' may be omitted from the address.  A
               blank line alone is equivalent to `.+1p'; it is useful
               for stepping through text.

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

          When reading a file, ed discards NUL characters and all
          characters after the last newline.

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

     SOURCE
          /sys/src/cmd/ed.c

     SEE ALSO
          sam(1), sed(1), regexp(6)

     DIAGNOSTICS
          ?name for inaccessible file; `?TMP' for temporary file over-
          flow; `?'  for errors in commands or other overflows.