
SED(1)                     BSD General Commands Manual                    SED(1)

𝐍𝐀𝐌𝐄
     𝘀𝗲𝗱 — stream editor

𝐒𝐘𝐍𝐎𝐏𝐒𝐈𝐒
     𝘀𝗲𝗱 [-𝗮𝐄𝗹𝗻𝗿𝘂] c̲o̲m̲m̲a̲n̲d̲ [f̲i̲l̲e̲ .̲.̲.̲]
     𝘀𝗲𝗱 [-𝗮𝐄𝗹𝗻𝗿𝘂] [-𝗲 c̲o̲m̲m̲a̲n̲d̲] [-𝗳 c̲o̲m̲m̲a̲n̲d̲_f̲i̲l̲e̲] [-𝐈[e̲x̲t̲e̲n̲s̲i̲o̲n̲]]
         [-𝗶[e̲x̲t̲e̲n̲s̲i̲o̲n̲]] [f̲i̲l̲e̲ .̲.̲.̲]

𝐃𝐄𝐒𝐂𝐑𝐈𝐏𝐓𝐈𝐎𝐍
     The 𝘀𝗲𝗱 utility reads the specified files, or the standard input if no
     files are specified, modifying the input as specified by a list of com‐
     mands.  The input is then written to the standard output.

     A single command may be specified as the first argument to 𝘀𝗲𝗱.  Multiple
     commands may be specified by using the -𝗲 or -𝗳 options.  All commands are
     applied to the input in the order they are specified regardless of their
     origin.

     The following options are available:

     -𝗮      The files listed as parameters for the “w” functions are created
             (or truncated) before any processing begins, by default.  The -𝗮
             option causes 𝘀𝗲𝗱 to delay opening each file until a command con‐
             taining the related “w” function is applied to a line of input.

     -𝐄      Interpret regular expressions as extended (modern) regular expres‐
             sions rather than basic regular expressions (BRE's).  The
             re_format(7) manual page fully describes both formats.

     -𝗲 c̲o̲m̲m̲a̲n̲d̲
             Append the editing commands specified by the c̲o̲m̲m̲a̲n̲d̲ argument to
             the list of commands.

     -𝗳 c̲o̲m̲m̲a̲n̲d̲_f̲i̲l̲e̲
             Append the editing commands found in the file c̲o̲m̲m̲a̲n̲d̲_f̲i̲l̲e̲ to the
             list of commands.  The editing commands should each be listed on a
             separate line.

     -𝐈[e̲x̲t̲e̲n̲s̲i̲o̲n̲]
             Edit files in-place, saving backups with the specified e̲x̲t̲e̲n̲s̲i̲o̲n̲.
             If no e̲x̲t̲e̲n̲s̲i̲o̲n̲ is given, no backup will be saved.  It is not rec‐
             ommended to give a zero-length e̲x̲t̲e̲n̲s̲i̲o̲n̲ when in-place editing
             files, as you risk corruption or partial content in situations
             where disk space is exhausted, etc.

             Note that in-place editing with -𝐈 still takes place in a single
             continuous line address space covering all files, although each
             file preserves its individuality instead of forming one output
             stream.  The line counter is never reset between files, address
             ranges can span file boundaries, and the “$” address matches only
             the last line of the last file.  (See S̲e̲d̲ A̲d̲d̲r̲e̲s̲s̲e̲s̲.)  That can
             lead to unexpected results in many cases of in-place editing, where
             using -𝗶 is desired.

     -𝗶[e̲x̲t̲e̲n̲s̲i̲o̲n̲]
             Edit files in-place similarly to -𝐈, but treat each file indepen‐
             dently from other files.  In particular, line numbers in each file
             start at 1, the “$” address matches the last line of the current
             file, and address ranges are limited to the current file.  (See S̲e̲d̲
             A̲d̲d̲r̲e̲s̲s̲e̲s̲.)  The net result is as though each file were edited by a
             separate 𝘀𝗲𝗱 instance.

     -𝗹      Make output line buffered.

     -𝗻      By default, each line of input is echoed to the standard output af‐
             ter all of the commands have been applied to it.  The -𝗻 option
             suppresses this behavior.

     -𝗿      Same as -𝐄 for compatibility with GNU sed.

     -𝘂      Make output unbuffered.

     The form of a 𝘀𝗲𝗱 command is as follows:

           [address[,address]]function[arguments]

     Whitespace may be inserted before the first address and the function por‐
     tions of the command.

     Normally, 𝘀𝗲𝗱 cyclically copies a line of input, not including its termi‐
     nating newline character, into a p̲a̲t̲t̲e̲r̲n̲ s̲p̲a̲c̲e̲, (unless there is something
     left after a “D” function), applies all of the commands with addresses that
     select that pattern space, copies the pattern space to the standard output,
     appending a newline, and deletes the pattern space.

     Some of the functions use a h̲o̲l̲d̲ s̲p̲a̲c̲e̲ to save all or part of the pattern
     space for subsequent retrieval.

   𝐒𝗲𝗱 𝐀𝗱𝗱𝗿𝗲𝘀𝘀𝗲𝘀
     An address is not required, but if specified must have one of the following
     formats:

           •   a number that counts input lines cumulatively across input files
               (or in each file independently if a -𝗶 option is in effect);

           •   a dollar (“$”) character that addresses the last line of input
               (or the last line of the current file if a -𝗶 option was speci‐
               fied);

           •   a context address that consists of a regular expression preceded
               and followed by a delimiter.  The closing delimiter can also op‐
               tionally be followed by the “i” character, to indicate that the
               regular expression is to be matched in a case-insensitive way.

     A command line with no addresses selects every pattern space.

     A command line with one address selects all of the pattern spaces that
     match the address.

     A command line with two addresses selects an inclusive range.  This range
     starts with the first pattern space that matches the first address.  The
     end of the range is the next following pattern space that matches the sec‐
     ond address.  If the second address is a number less than or equal to the
     line number first selected, only that line is selected.  The number in the
     second address may be prefixed with a (“+”) to specify the number of lines
     to match after the first pattern.  In the case when the second address is a
     context address, 𝘀𝗲𝗱 does not re-match the second address against the pat‐
     tern space that matched the first address.  Starting at the first line fol‐
     lowing the selected range, 𝘀𝗲𝗱 starts looking again for the first address.

     Editing commands can be applied to non-selected pattern spaces by use of
     the exclamation character (“!”) function.

   𝐒𝗲𝗱 𝐑𝗲𝗴𝘂𝗹𝗮𝗿 𝐄𝘅𝗽𝗿𝗲𝘀𝘀𝗶𝗼𝗻𝘀
     The regular expressions used in 𝘀𝗲𝗱, by default, are basic regular expres‐
     sions (BREs, see re_format(7) for more information), but extended (modern)
     regular expressions can be used instead if the -𝐄 flag is given.  In addi‐
     tion, 𝘀𝗲𝗱 has the following two additions to regular expressions:

     1.   In a context address, any character other than a backslash (“\”) or
          newline character may be used to delimit the regular expression.  The
          opening delimiter needs to be preceded by a backslash unless it is a
          slash.  For example, the context address \xabcx is equivalent to
          /abc/.  Also, putting a backslash character before the delimiting
          character within the regular expression causes the character to be
          treated literally.  For example, in the context address \xabc\xdefx,
          the RE delimiter is an “x” and the second “x” stands for itself, so
          that the regular expression is “abcxdef”.

     2.   The escape sequence \n matches a newline character embedded in the
          pattern space.  You cannot, however, use a literal newline character
          in an address or in the substitute command.

     One special feature of 𝘀𝗲𝗱 regular expressions is that they can default to
     the last regular expression used.  If a regular expression is empty, i.e.,
     just the delimiter characters are specified, the last regular expression
     encountered is used instead.  The last regular expression is defined as the
     last regular expression used as part of an address or substitute command,
     and at run-time, not compile-time.  For example, the command “/abc/s//XXX/”
     will substitute “XXX” for the pattern “abc”.

   𝐒𝗲𝗱 𝐅𝘂𝗻𝗰𝘁𝗶𝗼𝗻𝘀
     In the following list of commands, the maximum number of permissible ad‐
     dresses for each command is indicated by [0addr], [1addr], or [2addr], rep‐
     resenting zero, one, or two addresses.

     The argument t̲e̲x̲t̲ consists of one or more lines.  To embed a newline in the
     text, precede it with a backslash.  Other backslashes in text are deleted
     and the following character taken literally.

     The “r” and “w” functions take an optional file parameter, which should be
     separated from the function letter by white space.  Each file given as an
     argument to 𝘀𝗲𝗱 is created (or its contents truncated) before any input
     processing begins.

     The “b”, “r”, “s”, “t”, “w”, “y”, “!”, and “:” functions all accept addi‐
     tional arguments.  The following synopses indicate which arguments have to
     be separated from the function letters by white space characters.

     Two of the functions take a function-list.  This is a list of 𝘀𝗲𝗱 functions
     separated by newlines, as follows:

           { function
             function
             ...
             function
           }

     The “{” can be preceded by white space and can be followed by white space.
     The function can be preceded by white space.  The terminating “}” must be
     preceded by a newline, and may also be preceded by white space.

     [2addr] function-list
             Execute function-list only when the pattern space is selected.

     [1addr]a\
     text    Write t̲e̲x̲t̲ to standard output immediately before each attempt to
             read a line of input, whether by executing the “N” function or by
             beginning a new cycle.

     [2addr]b[label]
             Branch to the “:” function with the specified label.  If the label
             is not specified, branch to the end of the script.

     [2addr]c\
     text    Delete the pattern space.  With 0 or 1 address or at the end of a
             2-address range, t̲e̲x̲t̲ is written to the standard output.

     [2addr]d
             Delete the pattern space and start the next cycle.

     [2addr]D
             Delete the initial segment of the pattern space through the first
             newline character and start the next cycle.

     [2addr]g
             Replace the contents of the pattern space with the contents of the
             hold space.

     [2addr]G
             Append a newline character followed by the contents of the hold
             space to the pattern space.

     [2addr]h
             Replace the contents of the hold space with the contents of the
             pattern space.

     [2addr]H
             Append a newline character followed by the contents of the pattern
             space to the hold space.

     [1addr]i\
     text    Write t̲e̲x̲t̲ to the standard output.

     [2addr]l
             (The letter ell.)  Write the pattern space to the standard output
             in a visually unambiguous form.  This form is as follows:

                   backslash          \\
                   alert              \a
                   form-feed          \f
                   carriage-return    \r
                   tab                \t
                   vertical tab       \v

             Nonprintable characters are written as three-digit octal numbers
             (with a preceding backslash) for each byte in the character (most
             significant byte first).  Long lines are folded, with the point of
             folding indicated by displaying a backslash followed by a newline.
             The end of each line is marked with a “$”.

     [2addr]n
             Write the pattern space to the standard output if the default out‐
             put has not been suppressed, and replace the pattern space with the
             next line of input.

     [2addr]N
             Append the next line of input to the pattern space, using an embed‐
             ded newline character to separate the appended material from the
             original contents.  Note that the current line number changes.

     [2addr]p
             Write the pattern space to standard output.

     [2addr]P
             Write the pattern space, up to the first newline character to the
             standard output.

     [1addr]q
             Branch to the end of the script and quit without starting a new cy‐
             cle.

     [1addr]r file
             Copy the contents of f̲i̲l̲e̲ to the standard output immediately before
             the next attempt to read a line of input.  If f̲i̲l̲e̲ cannot be read
             for any reason, it is silently ignored and no error condition is
             set.

     [2addr]s/regular expression/replacement/flags
             Substitute the replacement string for the first instance of the
             regular expression in the pattern space.  Any character other than
             backslash or newline can be used instead of a slash to delimit the
             RE and the replacement.  Within the RE and the replacement, the RE
             delimiter itself can be used as a literal character if it is pre‐
             ceded by a backslash.

             An ampersand (“&”) appearing in the replacement is replaced by the
             string matching the RE.  The special meaning of “&” in this context
             can be suppressed by preceding it by a backslash.  The string “\#”,
             where “#” is a digit, is replaced by the text matched by the corre‐
             sponding backreference expression (see re_format(7)).

             A line can be split by substituting a newline character into it.
             To specify a newline character in the replacement string, precede
             it with a backslash.

             The value of f̲l̲a̲g̲s̲ in the substitute function is zero or more of
             the following:

                   N̲       Make the substitution only for the N̲'th occurrence of
                           the regular expression in the pattern space.

                   g       Make the substitution for all non-overlapping matches
                           of the regular expression, not just the first one.

                   p       Write the pattern space to standard output if a re‐
                           placement was made.  If the replacement string is
                           identical to that which it replaces, it is still con‐
                           sidered to have been a replacement.

                   w f̲i̲l̲e̲  Append the pattern space to f̲i̲l̲e̲ if a replacement was
                           made.  If the replacement string is identical to that
                           which it replaces, it is still considered to have
                           been a replacement.

                   i or I  Match the regular expression in a case-insensitive
                           way.

     [2addr]t [label]
             Branch to the “:” function bearing the label if any substitutions
             have been made since the most recent reading of an input line or
             execution of a “t” function.  If no label is specified, branch to
             the end of the script.

     [2addr]w f̲i̲l̲e̲
             Append the pattern space to the f̲i̲l̲e̲.

     [2addr]x
             Swap the contents of the pattern and hold spaces.

     [2addr]y/string1/string2/
             Replace all occurrences of characters in s̲t̲r̲i̲n̲g̲1̲ in the pattern
             space with the corresponding characters from s̲t̲r̲i̲n̲g̲2̲.  Any charac‐
             ter other than a backslash or newline can be used instead of a
             slash to delimit the strings.  Within s̲t̲r̲i̲n̲g̲1̲ and s̲t̲r̲i̲n̲g̲2̲, a back‐
             slash followed by any character other than a newline is that lit‐
             eral character, and a backslash followed by an ``n'' is replaced by
             a newline character.

     [2addr]!function
     [2addr]!function-list
             Apply the function or function-list only to the lines that are n̲o̲t̲
             selected by the address(es).

     [0addr]:label
             This function does nothing; it bears a label to which the “b” and
             “t” commands may branch.

     [1addr]=
             Write the line number to the standard output followed by a newline
             character.

     [0addr]
             Empty lines are ignored.

     [0addr]#
             The “#” and the remainder of the line are ignored (treated as a
             comment), with the single exception that if the first two charac‐
             ters in the file are “#n”, the default output is suppressed.  This
             is the same as specifying the -𝗻 option on the command line.

𝐄𝐍𝐕𝐈𝐑𝐎𝐍𝐌𝐄𝐍𝐓
     The COLUMNS, LANG, LC_ALL, LC_CTYPE and LC_COLLATE environment variables
     affect the execution of 𝘀𝗲𝗱 as described in environ(7).

𝐄𝐗𝐈𝐓 𝐒𝐓𝐀𝐓𝐔𝐒
     The 𝘀𝗲𝗱 utility exits 0 on success, and >0 if an error occurs.

𝐒𝐄𝐄 𝐀𝐋𝐒𝐎
     awk(1), ed(1), grep(1), regex(3), re_format(7)

𝐒𝐓𝐀𝐍𝐃𝐀𝐑𝐃𝐒
     The 𝘀𝗲𝗱 utility is expected to be a superset of the IEEE Std 1003.2
     (“POSIX.2”) specification.

     The -𝗮, -𝐄, -𝐈, and -𝗶 options, the prefixing “+” in the second member of
     an address range, as well as the “I” flag to the address regular expression
     and substitution command are non-standard FreeBSD extensions and may not be
     available on other operating systems.

𝐇𝐈𝐒𝐓𝐎𝐑𝐘
     A 𝘀𝗲𝗱 command, written by L. E. McMahon, appeared in Version 7 AT&T UNIX.

𝐀𝐔𝐓𝐇𝐎𝐑𝐒
     Diomidis D. Spinellis <dds@FreeBSD.org>

𝐁𝐔𝐆𝐒
     Multibyte characters containing a byte with value 0x5C (ASCII ‘\’) may be
     incorrectly treated as line continuation characters in arguments to the
     “a”, “c” and “i” commands.  Multibyte characters cannot be used as delim‐
     iters with the “s” and “y” commands.

BSD                               June 18, 2014                              BSD
