term% ls -F
term% pwd
term% cat index.txt
ED(1)                       General Commands Manual                      ED(1)

       ed - text editor

       ed [ - ] [ -x ] [ name ]

       Ed is the standard text editor.

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

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

       Commands to ed have a simple and regular structure: zero  or  more  ad‐
       dresses  followed  by  a single character command, possibly followed by
       parameters to the command.  These addresses specify one or  more  lines
       in the buffer.  Missing addresses are supplied by default.

       In  general,  only  one command may appear on a line.  Certain commands
       allow the addition of text to the buffer.  While ed is accepting  text,
       it  is  said to be in input mode.  In this mode, no commands are recog‐
       nized; all input is merely collected.  Input mode is left by  typing  a
       period `.' alone at the beginning of a line.

       Ed  supports  a limited form of regular expression notation.  A regular
       expression specifies a set of strings of characters.  A member of  this
       set of strings is said to be matched by the regular expression.  In the
       following specification for regular expressions  the  word  `character'
       means any character but newline.

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

       2.     A .  matches any character.

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

       4.     A nonempty string s bracketed [s] (or [^s]) matches any  charac‐
              ter in (or not in) s.  In s, \ has no special meaning, and ] may
              only appear as the first letter.  A substring a-b, with a and  b
              in  ascending  ASCII  order,  stands  for the inclusive range of
              ASCII characters.

       5.     A regular expression of form 1-4 followed by  *  matches  a  se‐
              quence of 0 or more matches of the regular expression.

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

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

       8.     A  regular  expression of form 1-8, x, followed by a regular ex‐
              pression of form 1-7, y matches a match  for  x  followed  by  a
              match  for  y,  with the x match being as long as possible while
              still permitting a y match.

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

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

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

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

       To understand addressing in ed it is necessary to know that at any time
       there is a current line.  Generally speaking, the current line  is  the
       last  line affected by a command; however, the exact effect on the cur‐
       rent line is discussed under the description of the command.  Addresses
       are constructed as follows.

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

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

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

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

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

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

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

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

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

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

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

       Addresses are separated from each other typically by a comma `,'.  They
       may  also  be  separated  by a semicolon `;'.  In this case the current
       line `.' is set to the previous address before the next address is  in‐
       terpreted.  This feature can be used to determine the starting line for
       forward and backward searches (`/', `?').  The second  address  of  any
       two-address  sequence must correspond to a line following the line cor‐
       responding to the first address.

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

       As mentioned, it is generally illegal for more than one command to  ap‐
       pear  on  a  line.  However, most commands may be suffixed by `p' or by
       `l', in which case the current line is either printed or listed respec‐
       tively in the way discussed below.

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

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

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

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

       E filename
            This  command  is the same as e, except that no diagnostic results
            when no w has been given since the last buffer alteration.

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

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


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

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

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

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

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

       (., .)p
            The print command prints the addressed lines.  `.'  is left at the
            last line printed.  The p command may be placed on the  same  line
            after any non-i/o command.

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

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

       Q    This command is the same as q, except that no  diagnostic  results
            when no w has been given since the last buffer alteration.

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

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

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

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

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

       (., .)u
            The  undo  command  restores the preceding contents of the current
            line, which must be the last line  in  which  a  substitution  was

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

       (1, $)w filename
            The  write command writes the addressed lines onto the given file.
            If the file does not exist, it is created mode 666  (readable  and
            writable  by  everyone).  The file name is remembered if there was
            no remembered file name already.  If no file name  is  given,  the
            remembered file name, if any, is used (see e and f commands).  `.'
            is unchanged.  If the command is successful, the number of charac‐
            ters written is printed.

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

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

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

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

            An  address  alone  on  a  line  causes  the  addressed line to be
            printed.  A blank line alone is equivalent to `.+1p'; it is useful
            for stepping through text.

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

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

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

       ed.hup: work is saved here if terminal hangs up

       B. W. Kernighan, A Tutorial Introduction to the ED Text Editor
       B. W. Kernighan, Advanced editing on UNIX
       sed(1), crypt(1)

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

       To protect against throwing away valuable work, a q  or  e  command  is
       considered  to be in error, unless a w has occurred since the last buf‐
       fer change.  A second q or e will be obeyed regardless.

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