Man Pages

ed(1p) - phpMan ed(1p) - phpMan

Command: man perldoc info search(apropos)  


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 dif-
       fer (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: command 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 Syn-
       tax 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 unspeci-
              fied.


STDIN
       The standard input shall be a text file consisting of commands, as described in the EXTENDED  DESCRIPTION  sec-
       tion.

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 Variables for  the  prece-
              dence 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 ele-
              ments within regular expressions.

       LC_CTYPE
              Determine  the locale for the interpretation of sequences of bytes of text data as characters (for exam-
              ple, single-byte as opposed to multi-byte characters in arguments and input files) and the  behavior  of
              character classes within regular expressions.

       LC_MESSAGES
              Determine  the locale that should be used to affect the format and contents of diagnostic messages writ-
              ten 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 command 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  com-
       mand 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 collected. 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 com-
       mand. 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 current 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 delim-
           ited 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 delimiter. 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 back-
           wards from the line preceding the current line toward the beginning 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 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 decimal 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  indi-
          cated number of lines to or from the address. A plus-sign or hyphen character not followed by a decimal num-
          ber 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 back-
       wards searches; see rules 5. and 6.

       Addresses can be omitted on either side of the comma or  semicolon  separator,  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 suffixed by the letter l, n, or p; in which case, except for the l,  n,  and  p  com-
       mands,  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 command 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 command 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 fol-
       lows 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 unspeci-
          fied 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 example, '/' ) 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 number 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 current 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 number 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  pathname  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 pathname 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 <new-
       line> 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 command. 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  com-
       mand  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 delimiter 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 <new-
       line> 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-execution 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 cur-
       rent line number shall be the value set by the last command successfully executed. (Note that the last  command
       successfully  executed  shall  be the G command itself if a command fails or the null command is specified.) 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  pre-
       ceded 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  subsequent '?' 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 let-
       ter  from  the  portable character 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  Definitions  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 char-
       acters 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  back-
       slash. 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, preceding each line by its line number and a
       <tab>; the current line number 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 written. 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 subse-
       quent 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 writ-
       ten, 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 suf-
       fix. 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 cur-
       rent 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 corre-
       sponding 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 substi-
       tute 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 replacement from beginning to end, the  fol-
       lowing  character  shall  lose its special 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 application shall ensure it escapes the  <newline>
       in  the  replacement by preceding 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  per-
       formed.  If  no  substitution  is performed, the current line number shall be unchanged.  If a line is split, a
       substitution shall be considered to have been performed 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 specified, 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 dur-
       ing 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 cre-
       ate the file, if it does not exist, or shall replace the contents of the existing file.  The  currently  remem-
       bered  pathname  shall not be changed unless there is no remembered pathname. If no pathname is given, the cur-
       rently 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 number 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 pathname. This
       usage of the write command with '!' shall not be considered as a "last w command that wrote the entire buffer",
       as  described  previously;  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 output 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 com-
       mand 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 written.  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 command, 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 implementations 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 Ver-
       sion 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 '!'  characters 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 commands.


        * 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 current line to that address.


        * BSD does not support the P command; moreover, in BSD it is synonymous 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 util-
       ities 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 implemen-
       tations document the file size limits imposed by ed in the conformance document. The  limit  {ED_LINE_MAX}  was
       also removed; therefore, 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 appearing in  the  line  is
       written  as  "\\"  so that the output is truly unambiguous. 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 utility 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  pat-
       terns.

       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 inter-
       pose 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 command 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 substitute command to
       delete that character.

       It is difficult under some modes of some versions of historical operating system terminal  drivers  to  distin-
       guish between an end-of-file condition and terminal disconnect. IEEE Std 1003.1-2001 does not require implemen-
       tations to distinguish between the two situations, which permits historical implementations of the  ed  utility
       on  historical  platforms to conform.  Implementations are encouraged to distinguish between the two, if possi-
       ble, 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 functionality, 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  combina-
       tion  with the semicolon delimiter, permits users to create commands based on ordered patterns in the file. For
       example, the command "3;/foo/;+2p" will display the first line after line 3 that contains 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, consisting solely of comma or semicolon separa-
       tors;  for  example,  ",,,"  or  ";;;" were considered an error. For consistency of address specification, 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 practice.

       Historically, ed accepted the '^' character as an address, in which case it was identical to the hyphen charac-
       ter. 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, Stan-
       dard  for Information Technology -- Portable Operating System Interface (POSIX), The Open Group Base Specifica-
       tions 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 Stan-
       dard, 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)