ed(category10-web-server.html) - phpMan

ED(1P)                     POSIX Programmer's Manual                    ED(1P)

PROLOG
       This  manual  page is part of the POSIX Programmer's Manual.  The Linux
       implementation of this interface may differ (consult the  corresponding
       Linux  manual page for details of Linux behavior), or the interface may
       not be implemented on Linux.
NAME
       ed - edit text
SYNOPSIS
       ed [-p string][-s][file]
DESCRIPTION
       The ed utility is a line-oriented text editor that uses two modes: com-
       mand mode and input mode. In command mode the input characters shall be
       interpreted as commands, and in input mode they shall be interpreted as
       text. See the EXTENDED DESCRIPTION section.
OPTIONS
       The  ed  utility  shall  conform  to  the  Base  Definitions  volume of
       IEEE Std 1003.1-2001, Section 12.2, Utility Syntax Guidelines.
       The following options shall be supported:
       -p  string
              Use string as  the  prompt  string  when  in  command  mode.  By
              default, there shall be no prompt string.
       -s     Suppress  the  writing of byte counts by e, E, r, and w commands
              and of the '!' prompt after a !command.

OPERANDS
       The following operand shall be supported:
       file   If the file argument is given, ed shall simulate an e command on
              the  file named by the pathname, file, before accepting commands
              from the standard input. If the file operand is '-', the results
              are unspecified.

STDIN
       The  standard  input  shall  be  a text file consisting of commands, as
       described in the EXTENDED DESCRIPTION section.
INPUT FILES
       The input files shall be text files.
ENVIRONMENT VARIABLES
       The following environment variables shall affect the execution of ed:
       HOME   Determine the pathname of the user's home directory.
       LANG   Provide a default value for the  internationalization  variables
              that  are  unset  or  null.  (See the Base Definitions volume of
              IEEE Std 1003.1-2001, Section  8.2,  Internationalization  Vari-
              ables  for the precedence of internationalization variables used
              to determine the values of locale categories.)
       LC_ALL If set to a non-empty string value, override the values  of  all
              the other internationalization variables.
       LC_COLLATE
              Determine  the  locale  for  the behavior of ranges, equivalence
              classes, and multi-character collating elements  within  regular
              expressions.
       LC_CTYPE
              Determine  the  locale  for  the  interpretation of sequences of
              bytes of text data as characters (for  example,  single-byte  as
              opposed  to  multi-byte characters in arguments and input files)
              and the behavior of character  classes  within  regular  expres-
              sions.
       LC_MESSAGES
              Determine  the  locale  that should be used to affect the format
              and contents of diagnostic messages written  to  standard  error
              and informative messages written to standard output.
       NLSPATH
              Determine the location of message catalogs for the processing of
              LC_MESSAGES .

ASYNCHRONOUS EVENTS
       The ed utility shall take the standard action for all signals (see  the
       ASYNCHRONOUS  EVENTS section in Utility Description Defaults ) with the
       following exceptions:
       SIGINT The ed utility shall interrupt its current activity,  write  the
              string "?\n" to standard output, and return to command mode (see
              the EXTENDED DESCRIPTION section).
       SIGHUP If the buffer is not empty and has changed since the last write,
              the  ed utility shall attempt to write a copy of the buffer in a
              file. First, the file named  ed.hup  in  the  current  directory
              shall  be  used;  if  that  fails,  the file named ed.hup in the
              directory named by the HOME environment variable shall be  used.
              In any case, the ed utility shall exit without returning to com-
              mand mode.
       SIGQUIT
              The ed utility shall ignore this event.

STDOUT
       Various editing commands and the prompting feature (see  -p)  write  to
       standard output, as described in the EXTENDED DESCRIPTION section.
STDERR
       The standard error shall be used only for diagnostic messages.
OUTPUT FILES
       The output files shall be text files whose formats are dependent on the
       editing commands given.
EXTENDED DESCRIPTION
       The ed utility shall operate on a copy  of  the  file  it  is  editing;
       changes  made  to  the  copy shall have no effect on the file until a w
       (write) command is given. The copy of the text is 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 that command. These addresses specify one or  more  lines
       in  the  buffer.  Every  command  that  requires  addresses has default
       addresses, so that the addresses very often can be omitted. If  the  -p
       option  is  specified,  the  prompt string shall be written to standard
       output before each command is read.
       In general, only one command can appear on  a  line.  Certain  commands
       allow text to be input. This text is placed in the appropriate place in
       the buffer. While ed is accepting text, it is said to be in input mode.
       In this mode, no commands shall be recognized; all input is merely col-
       lected. Input mode is terminated by entering a line consisting  of  two
       characters:  a period ( '.' ) followed by a <newline>. This line is not
       considered part of the input text.
   Regular Expressions in ed
       The ed utility shall support basic regular expressions, as described in
       the Base Definitions volume of IEEE Std 1003.1-2001, Section 9.3, Basic
       Regular Expressions. Since regular expressions in ed are always matched
       against  single  lines  (excluding  the  terminating <newline>s), never
       against any larger section of text, there  is  no  way  for  a  regular
       expression to match a <newline>.
       A null RE shall be equivalent to the last RE encountered.
       Regular expressions are used in addresses to specify lines, and in some
       commands (for example, the s substitute command) to specify portions of
       a line to be substituted.
   Addresses in ed
       Addressing  in  ed  relates to the current line. Generally, the current
       line is the last line affected by a command. The current line number is
       the  address  of the current line. If the edit buffer is not empty, the
       initial value for the current line shall be the last line in  the  edit
       buffer; otherwise, zero.
       Addresses shall be constructed as follows:
        1. The period character ( '.' ) shall address the current line.
        2. The  dollar  sign  character ( '$' ) shall address the last line of
           the edit buffer.
        3. The positive decimal number n shall address the  nth  line  of  the
           edit buffer.
        4. The  apostrophe-x  character  pair  ( "'x" ) shall address the line
           marked with the mark name character x, which shall be  a  lowercase
           letter from the portable character set. It shall be an error if the
           character has not been set to mark a line or if the line  that  was
           marked is not currently present in the edit buffer.
        5. A  BRE enclosed by slash characters ( '/' ) shall address the first
           line found by searching forwards from the line following  the  cur-
           rent  line  toward  the  end of the edit buffer and stopping at the
           first line for which the line excluding the  terminating  <newline>
           matches  the  BRE.  The BRE consisting of a null BRE delimited by a
           pair of slash characters shall address the next line for which  the
           line  excluding  the  terminating  <newline>  matches  the last BRE
           encountered. In addition, the second slash can be  omitted  at  the
           end  of  a  command  line. Within the BRE, a backslash-slash pair (
           "\/" ) shall represent a literal slash instead of  the  BRE  delim-
           iter.  If  necessary, the search shall wrap around to the beginning
           of the buffer and continue up to and including the current line, so
           that the entire buffer is searched.
        6. A  BRE  enclosed  by question-mark characters ( '?' ) shall address
           the first line found by searching backwards from the line preceding
           the  current line toward the beginning of the edit buffer and stop-
           ping at the first line for which the line excluding the terminating
           <newline>  matches the BRE. The BRE consisting of a null BRE delim-
           ited by a pair of question-mark characters ( "??" )  shall  address
           the  previous  line  for  which  the line excluding the terminating
           <newline> matches the last BRE encountered. In addition, the second
           question-mark  can  be omitted at the end of a command line. Within
           the BRE, a backslash-question-mark pair ( "\?" ) shall represent  a
           literal  question  mark instead of the BRE delimiter. If necessary,
           the search shall wrap around to the end of the buffer and  continue
           up  to and including the current line, so that the entire buffer is
           searched.
        7. A plus-sign ( '+' ) or hyphen character ( '-' ) followed by a deci-
           mal number shall address the current line plus or minus the number.
           A plus-sign or hyphen character not followed by  a  decimal  number
           shall address the current line plus or minus 1.
       Addresses  can  be followed by zero or more address offsets, optionally
       <blank>-separated. Address offsets are constructed as follows:
        * A plus-sign or hyphen character followed by a decimal  number  shall
          add  or  subtract, respectively, the indicated number of lines to or
          from the address. A plus-sign or hyphen character not followed by  a
          decimal number shall add or subtract 1 to or from the address.
        * A  decimal  number  shall  add  the indicated number of lines to the
          address.
       It shall not be an error for an intermediate address value to  be  less
       than zero or greater than the last line in the edit buffer. It shall be
       an error for the final address value to be less than  zero  or  greater
       than the last line in the edit buffer. It shall be an error if a search
       for a BRE fails to find a matching line.
       Commands accept zero, one, or two addresses. If more than the  required
       number  of  addresses  are  provided  to  a  command that requires zero
       addresses, it shall be an error. Otherwise, if more than  the  required
       number  of addresses are provided to a command, the addresses specified
       first shall be evaluated and then discarded until the maximum number of
       valid addresses remain, for the specified command.
       Addresses  shall  be  separated  from  each other by a comma ( ',' ) or
       semicolon character ( ';' ). In the case of a semicolon separator,  the
       current  line  ( '.' ) shall be set to the first address, and only then
       will the second address be calculated. This  feature  can  be  used  to
       determine  the  starting  line for forwards and backwards searches; see
       rules 5. and 6.
       Addresses can be omitted on either side of the comma or semicolon sepa-
       rator, in which case the resulting address pairs shall be as follows:
                               Specified   Resulting
                               ,           1 , $,
                               addr        1 , addr
                               addr ,      addr , addr
                               ;           . ; $
                               ; addr      . ; addr
                               addr ;      addr ; addr
       Any <blank>s included between addresses, address separators, or address
       offsets shall be ignored.
   Commands in ed
       In the following list of ed commands, the default addresses  are  shown
       in  parentheses.  The number of addresses shown in the default shall be
       the number expected by the command. The parentheses are not part of the
       address; they show that the given addresses are the default.
       It  is generally invalid for more than one command to appear on a line.
       However, any command (except e, E, f, q, Q, r, w, and !)  can  be  suf-
       fixed by the letter l, n, or p; in which case, except for the l, n, and
       p commands, the command shall be executed and then the new current line
       shall  be  written  as  described below under the l, n, and p commands.
       When an l, n, or p suffix is used with an l, n, or p command, the  com-
       mand  shall  write  to  standard  output  as described below, but it is
       unspecified whether the suffix writes the current  line  again  in  the
       requested  format or whether the suffix has no effect. For example, the
       pl command (base p command with an l suffix) shall  either  write  just
       the  current line or write it twice-once as specified for p and once as
       specified for l.  Also, the g, G, v, and V commands shall take  a  com-
       mand as a parameter.
       Each  address  component  can be preceded by zero or more <blank>s. The
       command letter can be preceded by zero or more <blank>s.  If  a  suffix
       letter  (  l,  n,  or p) is given, the application shall ensure that it
       immediately follows the command.
       The e, E, f, r, and w commands shall take an optional  file  parameter,
       separated from the command letter by one or more <blank>s.
       If  changes  have been made in the buffer since the last w command that
       wrote the entire buffer, ed shall warn the user if an attempt  is  made
       to  destroy  the  editor buffer via the e or q commands. The ed utility
       shall write the string:

              "?\n"
       (followed by an explanatory message if help mode has been  enabled  via
       the  H  command)  to standard output and shall continue in command mode
       with the current line number unchanged.  If  the  e  or  q  command  is
       repeated with no intervening command, it shall take effect.
       If a terminal disconnect is detected:
        * If the buffer is not empty and has changed since the last write, the
          ed utility shall attempt to write a copy of the  buffer  to  a  file
          named ed.hup in the current directory. If this write fails, ed shall
          attempt to write a copy of the buffer to a filename  ed.hup  in  the
          directory  named  by  the  HOME  environment variable. If both these
          attempts fail, ed shall exit without saving the buffer.
        * The ed utility shall not write the file to the currently  remembered
          pathname  or return to command mode, and shall terminate with a non-
          zero exit status.
       If an end-of-file is detected on standard input:
        * If the ed utility is in input mode, ed shall  terminate  input  mode
          and  return  to  command  mode.  It  is unspecified if any partially
          entered lines (that is, input text without a terminating  <newline>)
          are discarded from the input text.
        * If the ed utility is in command mode, it shall act as if a q command
          had been entered.
       If the closing delimiter of an RE or of a replacement string (for exam-
       ple,  '/'  )  in a g, G, s, v, or V command would be the last character
       before a <newline>, that delimiter can be omitted, in  which  case  the
       addressed  line  shall  be written. For example, the following pairs of
       commands are equivalent:

              s/s1/s2   s/s1/s2/p
              g/s1      g/s1/p
              ?s1       ?s1?
       If an invalid command is entered, ed shall write the string:

              "?\n"
       (followed by an explanatory message if help mode has been  enabled  via
       the  H  command)  to standard output and shall continue in command mode
       with the current line number unchanged.
   Append Command
       Synopsis:

              (.)a
              <text>
              .

       The a command shall read  the  given  text  and  append  it  after  the
       addressed line; the current line number shall become the address of the
       last inserted line or, if there were none, the addressed line.  Address
       0  shall be valid for this command; it shall cause the appended text to
       be placed at the beginning of the buffer.
   Change Command
       Synopsis:

              (.,.)c
              <text>
              .

       The c command shall delete the addressed lines, then accept input  text
       that replaces these lines; the current line shall be set to the address
       of the last line input; or, if there were none, at the line  after  the
       last  line  deleted; if the lines deleted were originally at the end of
       the buffer, the current line number shall be set to the address of  the
       new  last line; if no lines remain in the buffer, the current line num-
       ber shall be set to zero.  Address 0 shall be valid for  this  command;
       it shall be interpreted as if address 1 were specified.
   Delete Command
       Synopsis:

              (.,.)d

       The  d  command  shall delete the addressed lines from the buffer.  The
       address of the line after the last line deleted shall become  the  cur-
       rent  line  number;  if the lines deleted were originally at the end of
       the buffer, the current line number shall be set to the address of  the
       new  last line; if no lines remain in the buffer, the current line num-
       ber shall be set to zero.
   Edit Command
       Synopsis:

              e [file]

       The e command shall delete the entire contents of the buffer  and  then
       read  in  the file named by the pathname file.  The current line number
       shall be set to the address of the last line of the buffer. If no path-
       name is given, the currently remembered pathname, if any, shall be used
       (see the f command).  The number of bytes  read  shall  be  written  to
       standard  output,  unless the -s option was specified, in the following
       format:

              "%d\n", <number of bytes read>
       The name file shall be remembered for possible use as a  default  path-
       name in subsequent e, E, r, and w commands. If file is replaced by '!',
       the rest of the line shall be taken to be a shell  command  line  whose
       output is to be read. Such a shell command line shall not be remembered
       as the current file. All marks shall be discarded upon  the  completion
       of  a  successful  e  command. If the buffer has changed since the last
       time the entire buffer was  written,  the  user  shall  be  warned,  as
       described previously.
   Edit Without Checking Command
       Synopsis:

              E [file]

       The  E  command  shall possess all properties and restrictions of the e
       command except that the editor shall  not  check  to  see  whether  any
       changes have been made to the buffer since the last w command.
   Filename Command
       Synopsis:

              f [file]

       If  file  is given, the f command shall change the currently remembered
       pathname to file; whether the name is changed or  not,  it  shall  then
       write  the (possibly new) currently remembered pathname to the standard
       output in the following format:

              "%s\n", <pathname>
       The current line number shall be unchanged.
   Global Command
       Synopsis:

              (1,$)g/RE/command list

       In the g command, the first step shall be to mark every line for  which
       the  line  excluding  the  terminating  <newline> matches the given RE.
       Then, going sequentially from the beginning of the file to the  end  of
       the  file,  the  given  command  list shall be executed for each marked
       line, with the current line number set to the address of that line. Any
       line modified by the command list shall be unmarked. When the g command
       completes, the current line number shall have the value assigned by the
       last  command in the command list. If there were no matching lines, the
       current line number shall not be changed. A single command or the first
       of  a list of commands shall appear on the same line as the global com-
       mand. All lines of a multi-line list except  the  last  line  shall  be
       ended  with  a backslash preceding the terminating <newline>; the a, i,
       and c commands and associated input are permitted. The '.'  terminating
       input  mode  can be omitted if it would be the last line of the command
       list. An empty command list shall be equivalent to the p  command.  The
       use  of  the  g,  G,  v, V, and ! commands in the command list produces
       undefined results. Any character other than <space> or <newline> can be
       used instead of a slash to delimit the RE. Within the RE, the RE delim-
       iter itself can be used as a literal character if it is preceded  by  a
       backslash.
   Interactive Global Command
       Synopsis:

              (1,$)G/RE/

       In  the G command, the first step shall be to mark every line for which
       the line excluding the terminating  <newline>  matches  the  given  RE.
       Then, for every such line, that line shall be written, the current line
       number shall be set to the address of that line, and  any  one  command
       (other  than one of the a, c, i, g, G, v, and V commands) shall be read
       and executed. A <newline> shall act  as  a  null  command  (causing  no
       action to be taken on the current line); an '&' shall cause the re-exe-
       cution of the most recent non-null command executed within the  current
       invocation  of G. Note that the commands input as part of the execution
       of the G command can address and affect any lines in  the  buffer.  Any
       line  modified by the command shall be unmarked. The final value of the
       current line number shall be the value set by the last command success-
       fully executed. (Note that the last command successfully executed shall
       be the G command itself if a command fails or the null command is spec-
       ified.)  If there were no matching lines, the current line number shall
       not be changed. The G command can be terminated by a SIGINT signal. Any
       character  other  than  <space>  or  <newline> can be used instead of a
       slash to delimit the RE and the replacement.  Within  the  RE,  the  RE
       delimiter  itself  can be used as a literal character if it is preceded
       by a backslash.
   Help Command
       Synopsis:

              h

       The h command shall write a  short  message  to  standard  output  that
       explains  the reason for the most recent '?'  notification. The current
       line number shall be unchanged.
   Help-Mode Command
       Synopsis:

              H

       The H command shall cause ed to enter a mode  in  which  help  messages
       (see  the h command) shall be written to standard output for all subse-
       quent '?' notifications. The H command alternately shall turn this mode
       on  and  off; it is initially off. If the help-mode is being turned on,
       the H command also explains the previous '?' notification, if there was
       one. The current line number shall be unchanged.
   Insert Command
       Synopsis:

              (.)i
              <text>
              .

       The  i  command  shall insert the given text before the addressed line;
       the current line is set to the last inserted  line  or,  if  there  was
       none,  to  the  addressed line. This command differs from the a command
       only in the placement of the input text. Address 0 shall be  valid  for
       this command; it shall be interpreted as if address 1 were specified.
   Join Command
       Synopsis:

              (.,.+1)j

       The  j  command shall join contiguous lines by removing the appropriate
       <newline>s. If exactly one address is  given,  this  command  shall  do
       nothing.  If  lines are joined, the current line number shall be set to
       the address of the joined line;  otherwise,  the  current  line  number
       shall be unchanged.
   Mark Command
       Synopsis:

              (.)kx

       The  k  command  shall  mark  the addressed line with name x, which the
       application shall ensure is a lowercase letter from the portable  char-
       acter  set. The address "'x" shall then refer to this line; the current
       line number shall be unchanged.
   List Command
       Synopsis:

              (.,.)l

       The l command shall write to standard output the addressed lines  in  a
       visually  unambiguous  form.  The characters listed in the Base Defini-
       tions volume of IEEE Std 1003.1-2001, Table 5-1, Escape  Sequences  and
       Associated  Actions  ( '\\', '\a', '\b', '\f', '\r', '\t', '\v' ) shall
       be written as the corresponding escape sequence; the '\n' in that table
       is  not  applicable. Non-printable characters not in the table shall be
       written as one three-digit octal number  (with  a  preceding  backslash
       character)  for  each  byte  in  the  character  (most significant byte
       first). If the size of a byte on the system is greater than nine  bits,
       the format used for non-printable characters is implementation-defined.
       Long  lines  shall  be  folded,  with the point of folding indicated by
       <newline> preceded by a backslash; the length at which  folding  occurs
       is  unspecified,  but  should be appropriate for the output device. The
       end of each line shall be marked with a '$', and '$' characters  within
       the  text shall be written with a preceding backslash. An l command can
       be appended to any other command other than e, E, f, q, Q, r, w, or  !.
       The  current  line  number shall be set to the address of the last line
       written.
   Move Command
       Synopsis:

              (.,.)maddress

       The m command shall reposition  the  addressed  lines  after  the  line
       addressed  by  address.  Address 0 shall be valid for address and cause
       the addressed lines to be moved to the  beginning  of  the  buffer.  It
       shall  be  an  error if address address falls within the range of moved
       lines. The current line number shall be set to the address of the  last
       line moved.
   Number Command
       Synopsis:

              (.,.)n

       The  n command shall write to standard output the addressed lines, pre-
       ceding each line by its line number and a <tab>; the current line  num-
       ber shall be set to the address of the last line written. The n command
       can be appended to any command other than e, E, f, q, Q, r, w, or !.
   Print Command
       Synopsis:

              (.,.)p

       The p command shall write to standard output the addressed  lines;  the
       current  line number shall be set to the address of the last line writ-
       ten. The p command can be appended to any command other than e,  E,  f,
       q, Q, r, w, or !.
   Prompt Command
       Synopsis:

              P

       The  P  command  shall  cause ed to prompt with an asterisk ( '*' ) (or
       string, if -p is specified) for all subsequent commands. The P  command
       alternatively shall turn this mode on and off; it shall be initially on
       if the -p option is specified; otherwise, off. The current line  number
       shall be unchanged.
   Quit Command
       Synopsis:

              q

       The  q  command shall cause ed to exit. If the buffer has changed since
       the last time the entire buffer was written, the user shall be  warned,
       as described previously.
   Quit Without Checking Command
       Synopsis:

              Q

       The  Q  command shall cause ed to exit without checking whether changes
       have been made in the buffer since the last w command.
   Read Command
       Synopsis:

              ($)r [file]

       The r command shall read in the file named by  the  pathname  file  and
       append  it  after the addressed line. If no file argument is given, the
       currently remembered pathname, if any, shall be used (see the e  and  f
       commands).   The  currently  remembered  pathname  shall not be changed
       unless there is no remembered pathname. Address 0 shall be valid for  r
       and  shall cause the file to be read at the beginning of the buffer. If
       the read is successful, and -s was not specified, the number  of  bytes
       read shall be written to standard output in the following format:

              "%d\n", <number of bytes read>
       The  current  line  number shall be set to the address of the last line
       read in. If file is replaced by '!', the rest  of  the  line  shall  be
       taken  to  be  a  shell command line whose output is to be read. Such a
       shell command line shall not be remembered as the current pathname.
   Substitute Command
       Synopsis:

              (.,.)s/RE/replacement/flags

       The s command shall search each addressed line for an occurrence of the
       specified  RE  and  replace  either  the  first or all (non-overlapped)
       matched strings with the replacement; see the following description  of
       the  g  suffix.  It  is  an  error  if  the substitution fails on every
       addressed line. Any character other than <space> or  <newline>  can  be
       used  instead  of a slash to delimit the RE and the replacement. Within
       the RE, the RE delimiter itself can be used as a literal  character  if
       it  is  preceded  by  a backslash. The current line shall be set to the
       address of the last line on which a substitution occurred.
       An ampersand ( '&' ) appearing in the replacement shall be replaced  by
       the  string matching the RE on the current line. The special meaning of
       '&' in this context can be suppressed by preceding it by backslash.  As
       a  more general feature, the characters '\n', where n is a digit, shall
       be replaced by the text matched  by  the  corresponding  back-reference
       expression.  When  the  character  '%'  is  the  only  character in the
       replacement, the replacement used in the most recent substitute command
       shall  be used as the replacement in the current substitute command; if
       there was no previous substitute command, the use of '%' in this manner
       shall be an error. The '%' shall lose its special meaning when it is in
       a replacement string of more than one character or  is  preceded  by  a
       backslash.  For each backslash ( '\' ) encountered in scanning replace-
       ment from beginning to end, the following character shall lose its spe-
       cial  meaning (if any). It is unspecified what special meaning is given
       to any character other than '&', '\', '%', or digits.
       A line can be split by substituting a <newline> into it.  The  applica-
       tion  shall  ensure it escapes the <newline> in the replacement by pre-
       ceding it by backslash. Such substitution cannot be done as part of a g
       or  v command list. The current line number shall be set to the address
       of the last line on which a substitution is performed. If no  substitu-
       tion  is  performed,  the current line number shall be unchanged.  If a
       line is split, a substitution shall be considered  to  have  been  per-
       formed  on each of the new lines for the purpose of determining the new
       current line number. A substitution shall be considered  to  have  been
       performed  even  if  the  replacement string is identical to the string
       that it replaces.
       The application shall ensure that the value of flags is  zero  or  more
       of:
       count  Substitute  for  the  countth occurrence only of the RE found on
              each addressed line.
       g      Globally substitute for all non-overlapping instances of the  RE
              rather  than  just the first one. If both g and count are speci-
              fied, the results are unspecified.
       l      Write to standard output the final line in which a  substitution
              was  made. The line shall be written in the format specified for
              the l command.
       n      Write to standard output the final line in which a  substitution
              was  made. The line shall be written in the format specified for
              the n command.
       p      Write to standard output the final line in which a  substitution
              was  made. The line shall be written in the format specified for
              the p command.

   Copy Command
       Synopsis:

              (.,.)taddress

       The t command shall be equivalent to the m command, except that a  copy
       of the addressed lines shall be placed after address address (which can
       be 0); the current line number shall be set to the address of the  last
       line added.
   Undo Command
       Synopsis:

              u

       The  u command shall nullify the effect of the most recent command that
       modified anything in the buffer, namely the most recent a, c, d, g,  i,
       j, m, r, s, t, u, v, G, or V command. All changes made to the buffer by
       a g, G, v, or V global command shall be undone as a single  change;  if
       no  changes were made by the global command (such as with g/RE/ p), the
       u command shall have no effect. The current line number shall be set to
       the value it had immediately before the command being undone started.
   Global Non-Matched Command
       Synopsis:

              (1,$)v/RE/command list

       This  command  shall  be equivalent to the global command g except that
       the lines that are marked during the first  step  shall  be  those  for
       which  the  line excluding the terminating <newline> does not match the
       RE.
   Interactive Global Not-Matched Command
       Synopsis:

              (1,$)V/RE/

       This command shall be equivalent to the interactive  global  command  G
       except  that  the  lines that are marked during the first step shall be
       those for which the line excluding the terminating <newline>  does  not
       match the RE.
   Write Command
       Synopsis:

              (1,$)w [file]

       The  w  command  shall write the addressed lines into the file named by
       the pathname file. The command shall create the file, if  it  does  not
       exist,  or  shall  replace  the contents of the existing file. The cur-
       rently remembered pathname shall not be  changed  unless  there  is  no
       remembered  pathname. If no pathname is given, the currently remembered
       pathname, if any, shall be used (see the e and f commands); the current
       line  number shall be unchanged. If the command is successful, the num-
       ber of bytes written shall be written to standard output, unless the -s
       option was specified, in the following format:

              "%d\n", <number of bytes written>
       If  file  begins  with '!', the rest of the line shall be taken to be a
       shell command line whose standard input shall be the  addressed  lines.
       Such  a shell command line shall not be remembered as the current path-
       name. This usage of the write command with '!' shall not be  considered
       as a "last w command that wrote the entire buffer", as described previ-
       ously; thus, this alone shall not prevent the warning to the user if an
       attempt is made to destroy the editor buffer via the e or q commands.
   Line Number Command
       Synopsis:

              ($)=

       The line number of the addressed line shall be written to standard out-
       put in the following format:

              "%d\n", <line number>
       The current line number shall be unchanged by this command.
   Shell Escape Command
       Synopsis:

              !command

       The remainder of the line after the '!' shall be sent  to  the  command
       interpreter  to be interpreted as a shell command line. Within the text
       of that shell command  line,  the  unescaped  character  '%'  shall  be
       replaced  with  the  remembered pathname; if a '!' appears as the first
       character of the command, it shall be replaced with  the  text  of  the
       previous  shell  command executed via '!' . Thus, "!!" shall repeat the
       previous !command. If any replacements of '%' or '!' are performed, the
       modified line shall be written to the standard output before command is
       executed. The ! command shall write:

              "!\n"
       to standard output upon completion, unless the -s option is  specified.
       The current line number shall be unchanged.
   Null Command
       Synopsis:

              (.+1)

       An  address  alone on a line shall cause the addressed line to be writ-
       ten.  A <newline> alone shall be equivalent to "+1p" . The current line
       number shall be set to the address of the written line.
EXIT STATUS
       The following exit values shall be returned:
        0     Successful completion without any file or command errors.
       >0     An error occurred.

CONSEQUENCES OF ERRORS
       When  an  error in the input script is encountered, or when an error is
       detected that is a consequence of the data (not) present in the file or
       due to an external condition such as a read or write error:
        * If  the standard input is a terminal device file, all input shall be
          flushed, and a new command read.
        * If the standard input is a regular file, ed shall terminate  with  a
          non-zero exit status.
       The following sections are informative.
APPLICATION USAGE
       Because  of  the  extremely terse nature of the default error messages,
       the prudent script writer begins the ed input commands with an  H  com-
       mand, so that if any errors do occur at least some clue as to the cause
       is made available.
       In previous versions, an obsolescent - option was described.   This  is
       no  longer specified. Applications should use the -s option. Using - as
       a file operand now produces unspecified results. This allows  implemen-
       tations to continue to support the former required behavior.
EXAMPLES
       None.
RATIONALE
       The  initial description of this utility was adapted from the SVID.  It
       contains some features not found in Version 7 or  BSD-derived  systems.
       Some of the differences between the POSIX and BSD ed utilities include,
       but need not be limited to:
        * The BSD - option does not suppress the '!' prompt after a ! command.
        * BSD does not support the special meanings of the '%' and '!'   char-
          acters within a ! command.
        * BSD does not support the addresses ';' and ',' .
        * BSD  allows  the  command/suffix  pairs pp, ll, and so on, which are
          unspecified in this volume of IEEE Std 1003.1-2001.
        * BSD does not support the '!' character part of the e, r, or  w  com-
          mands.
        * A  failed  g  command  in  BSD sets the line number to the last line
          searched if there are no matches.
        * BSD does not default the command list to the p command.
        * BSD does not support the G, h, H, n, or V commands.
        * On BSD, if there is no inserted text, the insert command changes the
          current line to the referenced line -1; that is, the line before the
          specified line.
        * On BSD, the join command with only a single address changes the cur-
          rent line to that address.
        * BSD  does  not support the P command; moreover, in BSD it is synony-
          mous with the p command.
        * BSD does not support the undo of the commands j, m, r, s, or t.
        * The Version 7 ed command W, and the BSD ed commands W, wq, and z are
          not present in this volume of IEEE Std 1003.1-2001.
       The -s option was added to allow the functionality of the now withdrawn
       - option in a manner compatible with the Utility Syntax Guidelines.
       In early proposals there was a limit, {ED_FILE_MAX}, that described the
       historical  limitations of some ed utilities in their handling of large
       files; some of these have had problems with files  larger  than  100000
       bytes.  It  was  this  limitation  that  prompted much of the desire to
       include a split command in this volume of  IEEE Std 1003.1-2001.  Since
       this  limit  was  removed, this volume of IEEE Std 1003.1-2001 requires
       that implementations document the file size limits imposed by ed in the
       conformance  document. The limit {ED_LINE_MAX} was also removed; there-
       fore, the global limit {LINE_MAX} is used for input and output lines.
       The manner in which the l command writes non-printable  characters  was
       changed  to  avoid the historical backspace-overstrike method. On video
       display terminals, the overstrike is ambiguous because  most  terminals
       simply  replace  overstruck  characters, making the l format not useful
       for its intended purpose of unambiguously understanding the content  of
       the  line.  The  historical backslash escapes were also ambiguous. (The
       string "a\0011" could represent a line containing those six  characters
       or  a  line  containing  the three characters 'a', a byte with a binary
       value of 1, and a 1.) In the format required here, a backslash  appear-
       ing  in  the  line is written as "\\" so that the output is truly unam-
       biguous. The method of marking the ends of lines was adopted  from  the
       ex  editor  and is required for any line ending in <space>s; the '$' is
       placed on all lines so that a real '$' at the end of a line  cannot  be
       misinterpreted.
       Systems with bytes too large to fit into three octal digits must devise
       other means of displaying non-printable characters.  Consideration  was
       given  to  requiring that the number of octal digits be large enough to
       hold a byte, but this seemed to be too confusing  for  applications  on
       the  vast majority of systems where three digits are adequate. It would
       be theoretically possible for the application to use the getconf  util-
       ity  to  find  out  the CHAR_BIT value and deal with such an algorithm;
       however, there is really no portable way that an  application  can  use
       the  octal  values of the bytes across various coded character sets, so
       the additional specification was not worthwhile.
       The description of how a NUL is written was removed. The NUL  character
       cannot be in text files, and this volume of IEEE Std 1003.1-2001 should
       not dictate behavior in the case of undefined, erroneous input.
       Unlike some of the other editing utilities, the filenames  accepted  by
       the E, e, R, and r commands are not patterns.
       Early  proposals  stated  that  the -p option worked only when standard
       input was associated with a terminal device. This has been  changed  to
       conform to historical implementations, thereby allowing applications to
       interpose themselves between a user and the ed utility.
       The form of the substitute command that uses the n suffix  was  limited
       in  some historical documentation (where this was described incorrectly
       as "backreferencing"). This limit has been omitted because there is  no
       reason  why an editor processing lines of {LINE_MAX} length should have
       this restriction. The command s/x/X/2047 should be able  to  substitute
       the 2047th occurrence of 'x' on a line.
       The  use  of  printing commands with printing suffixes (such as pn, lp,
       and so on) was made unspecified because BSD-based systems  allow  this,
       whereas System V does not.
       Some  BSD-based systems exit immediately upon receipt of end-of-file if
       all of the lines in the file have been deleted. Since  this  volume  of
       IEEE Std 1003.1-2001  refers  to  the  q command in this instance, such
       behavior is not allowed.
       Some historical implementations returned exit status zero even if  com-
       mand  errors  had  occurred;  this  is  not  allowed  by this volume of
       IEEE Std 1003.1-2001.
       Some historical implementations contained a bug that allowed  a  single
       period  to  be entered in input mode as <backslash> <period> <newline>.
       This is not allowed by ed because there is no description  of  escaping
       any  of  the characters in input mode; backslashes are entered into the
       buffer exactly as typed. The typical method of entering a single period
       has  been to precede it with another character and then use the substi-
       tute command to delete that character.
       It is difficult under some modes of some versions of historical operat-
       ing  system terminal drivers to distinguish between an end-of-file con-
       dition and terminal disconnect. IEEE Std 1003.1-2001 does  not  require
       implementations  to  distinguish between the two situations, which per-
       mits historical implementations of the ed utility on  historical  plat-
       forms  to  conform.   Implementations  are  encouraged  to  distinguish
       between the two, if possible, and take appropriate action  on  terminal
       disconnect.
       Historically,  ed  accepted  a zero address for the a and r commands in
       order to insert text at the start of the edit buffer. When  the  buffer
       was  empty  the command .= returned zero. IEEE Std 1003.1-2001 requires
       conformance to historical practice.
       For consistency with the a and r commands and better  user  functional-
       ity,  the  i  and c commands must also accept an address of 0, in which
       case 0i is treated as 1i and likewise for the c command.
       All of the following are valid addresses:
       +++    Three lines after the current line.
       /pattern/-
              One line before the next occurrence of pattern.
       -2     Two lines before the current line.
       3 ---- 2
              Line one (note the intermediate negative address).
       1 2 3  Line six.

       Any number of addresses can be provided to commands  taking  addresses;
       for  example,  "1,2,3,4,5p"  prints  lines  4 and 5, because two is the
       greatest valid number of addresses accepted by the print command. This,
       in  combination  with  the semicolon delimiter, permits users to create
       commands based on ordered patterns in the file. For example,  the  com-
       mand  "3;/foo/;+2p"  will display the first line after line 3 that con-
       tains the pattern foo, plus the next two lines. Note that  the  address
       "3;" must still be evaluated before being discarded, because the search
       origin for the "/foo/" command depends on this.
       Historically, ed disallowed address chains, as  discussed  above,  con-
       sisting  solely of comma or semicolon separators; for example, ",,," or
       ";;;" were considered an error. For consistency of  address  specifica-
       tion,  this  restriction  is removed. The following table lists some of
       the address forms now possible:
              Address  Addr1  Addr2  Status      Comment
              7,       7      7      Historical
              7,5,     5      5      Historical
              7,5,9    5      9      Historical
              7,9      7      9      Historical
              7,+      7      8      Historical
              ,        1      $      Historical
              ,7       1      7      Extension
              ,,       $      $      Extension
              ,;       $      $      Extension
              7;       7      7      Historical
              7;5;     5      5      Historical
              7;5;9    5      9      Historical
              7;5,9    5      9      Historical
              7;$;4    $      4      Historical  Valid, but erroneous.
              7;9      7      9      Historical
              7;+      7      8      Historical
              ;        .      $      Historical
              ;7       .      7      Extension
              ;;       $      $      Extension
              ;,       $      $      Extension
       Historically, values could be added  to  addresses  by  including  them
       after  one  or  more  <blank>s; for example, "3 - 5p" wrote the seventh
       line of the file, and "/foo/ 5" was the same as  "5 /foo/"  .  However,
       only  absolute  values  could  be  added; for example, "5 /foo/" was an
       error. IEEE Std 1003.1-2001 requires conformance  to  historical  prac-
       tice.
       Historically,  ed  accepted  the  '^' character as an address, in which
       case it was identical to  the  hyphen  character.  IEEE Std 1003.1-2001
       does not require or prohibit this behavior.
FUTURE DIRECTIONS
       None.
SEE ALSO
       Utility Description Defaults, ex, sed, sh, vi
COPYRIGHT
       Portions  of  this text are reprinted and reproduced in electronic form
       from IEEE Std 1003.1, 2003 Edition, Standard for Information Technology
       --  Portable  Operating  System  Interface (POSIX), The Open Group Base
       Specifications Issue 6, Copyright (C) 2001-2003  by  the  Institute  of
       Electrical  and  Electronics  Engineers, Inc and The Open Group. In the
       event of any discrepancy between this version and the original IEEE and
       The  Open Group Standard, the original IEEE and The Open Group Standard
       is the referee document. The original Standard can be  obtained  online
       at http://www.opengroup.org/unix/online.html .

IEEE/The Open Group                  2003                               ED(1P)