NAME

ed - edit text

 SYNOPSIS

ed [-p string][-s][file]

ed [-p string][-][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 are interpreted as commands, and in input mode they are interpreted as text. See the EXTENDED DESCRIPTION section.

 OPTIONS

The ed utility supports the XBD specification, Utility Syntax Guidelines  ,  except for its non-standard usage of "-".

The following options are supported:

-p string

Use string as the prompt string when in command mode. By default, there is no prompt string.

-s

Suppress the writing of byte counts by e, E, r and w commands and of the "!" prompt after a !command.

-

Same as the -s option.

 OPERANDS

The following operand is supported:

file

If the file argument is given, ed will simulate an e command on the file named by the pathname, file, before accepting commands from the standard input.

 STDIN

The standard input must be a text file consisting of commands, as described in the EXTENDED DESCRIPTION section.

 INPUT FILES

The input files must be text files.

 ENVIRONMENT VARIABLES

The following environment variables affect the execution of ed:

HOME

Determine the pathname of the user's home directory.

LANG

Provide a default value for the internationalisation variables that are unset or null. If LANG is unset or null, the corresponding value from the implementation-dependent default locale will be used. If any of the internationalisation variables contains an invalid setting, the utility will behave as if none of the variables had been defined.

LC_ALL

If set to a non-empty string value, override the values of all the other internationalisation variables.

LC_COLLATE

Determine the locale for the behaviour 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- as opposed to multi-byte characters in arguments and input files) and the behaviour of character classes within regular expressions.

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 catalogues for the processing of LC_MESSAGES .

 ASYNCHRONOUS EVENTS

The ed utility will take the standard action for all signals (see the ASYNCHRONOUS EVENTS section in Utility Description Defaults ) with the following exceptions:

SIGINT

The ed utility will 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 will attempt to write a copy of the buffer in a file. First, the file named ed.hup in the current directory will be used; if that fails, the file named ed.hup in the directory named by the HOME environment variable will be used. In any case, the ed utility will exit without returning to command mode.

 STDOUT

Various editing commands and the prompting feature (see -p) write to standard output, as described in the EXTENDED DESCRIPTION section.

 STDERR

Used only for diagnostic messages.

 OUTPUT FILES

The output files are text files whose formats are dependent on the editing commands given.

 EXTENDED DESCRIPTION

The ed utility operates on a copy of the file it is editing; changes made to the copy will 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 will 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 are recognised; all input is merely collected. Input mode is terminated by entering a line consisting of two characters: a period (.) followed by a newline character. This line is not considered part of the input text.

 Regular Expressions in ed

The ed utility supports basic regular expressions, as described in the XBD specification, Basic Regular Expressions  . Since regular expressions in ed are always matched against single lines, never against any larger section of text, there is no way for a regular expression to match a newline character. A null RE is 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 (line number) of the current line. The exact effect on the current line number is discussed under the description of each command. The f, h, H, k, P, w, "=" and "!" commands do not modify the current line number.

Addresses are constructed as follows:

1. The character "." (period) addresses the current line.

2. The character "$" addresses the last line of the buffer.

3. A positive decimal number n addresses the nth line of the buffer. The first line in the buffer is line number 1.

4. 'x addresses the line marked with the mark name character x, which must be a lower-case letter from the portable character set. Lines can be marked with the k command.

5. An RE enclosed by slashes (/) addresses the first line found by searching forward from the line following the current line toward the end of the buffer and stopping at the first line containing a string matching the RE. An address consisting of a null RE delimited by slashes (//) addresses the next line containing the last RE encountered. If necessary, the search will wrap around to the beginning of the buffer and continue up to and including the current line, so that the entire buffer is searched. Within the RE, the sequence \/ represents a literal slash instead of the RE delimiter.

6. An RE enclosed in question-marks (?) addresses the first line found by searching backward from the line preceding the current line toward the beginning of the buffer and stopping at the first line containing a string matching the RE. If necessary, the search wraps around to the end of the buffer and continues up to and including the current line. Within the RE, the sequence \? represents a literal question-mark instead of the RE delimiter.

7. An address followed by a plus sign (+) or a minus sign (-) followed by a decimal number specifies that address plus (respectively minus) the indicated number of lines. The plus sign can be omitted.

8. If an address begins with "+" or "-", the addition or subtraction is taken with respect to the current line number; for example, -5 is understood to mean .-5.

9. If an address ends with "+" or "-", then 1 will be added to or subtracted from the address, respectively. As a consequence of this rule and of rule 8 immediately above, the address "-" refers to the line preceding the current line. Moreover, trailing "+" and "-" characters have a cumulative effect, so -- refers to the current line number less 2.

10. A comma (,) stands for the address pair 1,$, while a semicolon (;) stands for the pair .,$.

Commands require zero, one or two addresses. Commands that require no addresses regard the presence of an address as an error. Commands that accept one or two addresses assume default addresses when no addresses are given. If one address is given to a command that allows two addresses, the command will operate as if it were specified as:

given_address;. command

If more addresses are given than such a command requires, the results are undefined.

Typically, addresses are separated from each other by a comma. They can also be separated by a semicolon. In the latter case, the current line number (.) is 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 forward and backward searches (see rules 5 and 6 above). The second address of any two-address sequence corresponds to a line that does not precede, in the buffer, the line corresponding to the first address.

 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 are 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 commands, the command will be executed and then the new current line will 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 will 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) will either write just the current line or will write it twice once as specified for p and once as specified for l. Also, the g, G, v and V commands takes a command as a parameter.

Each address component can be preceded by zero or more blank characters. The command letter can be preceded by zero or more blank characters. If a suffix letter (l, n or p) is given, it must immediately follow the command.

The e, E, f, r and w commands take an optional file parameter, separated from the command letter by one or more blank characters.

If changes have been made in the buffer since the last w command that wrote the entire buffer, ed will warn the user if an attempt is made to destroy the editor buffer via the e or q commands. The ed utility will write the string:

"?\n"

(followed by an explanatory message if help mode has been enabled via the H command) to standard output and will continue in command mode with the current line number unchanged. If the e or q command is repeated with no intervening command, it will take effect.

If an end-of-file is detected on standard input when a command is expected, the ed utility acts 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 character, that delimiter can be omitted, in which case the addressed line is 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 will write the string:

"?\n"

(followed by an explanatory message if help mode has been enabled via the H command) to standard output and will continue in command mode with the current line number unchanged.

 Append Command

Synopsis:	(.)a
	<text>
	.

The a command reads the given text and appends it after the addressed line; the current line number will become the address of the last inserted line or, if there were none, the addressed line. Address 0 is valid for this command; it causes the appended text to be placed at the beginning of the buffer.

 Change Command

Synopsis:	(.,.)c
	<text>
	.

The c command deletes the addressed lines, then accepts input text that replaces these lines; the current line will 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 will be set to the address of the new last line; if no lines remain in the buffer, the current line number will be set to zero.

 Delete Command

Synopsis:	(.,.)d

The d command deletes the addressed lines from the buffer. The address of the line after the last line deleted will become the current line number; if the lines deleted were originally at the end of the buffer, the current line number will be set to the address of the new last line; if no lines remain in the buffer, the current line number will be set to zero.

 Edit Command

Synopsis:	e [file]

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

"%d\n", <number of bytes read>

The name file will 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 will be taken to be a shell command line whose output is to be read. Such a shell command line is not remembered as the current file. All marks will 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 will be warned, as described previously.

 Edit Without Checking Command

Synopsis:	E [file]

The E command possesses all properties and restrictions of the e command except that the editor will not check to see if 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 will change the currently remembered pathname to file; whether the name is changed or not, it then will write the (possibly new) currently remembered pathname to the standard output in the following format:

"%s\n", <pathname>

The current line number is unchanged.

 Global Command

Synopsis:	(1,$)g/RE/command list

In the g command, the first step is to mark every line that matches the given RE. Then, for every such line, the given command list will be executed with the current line number set to the address of that line. When the g command completes, the current line number will have the value assigned by the last command in the command list. If there were no matching lines, the current line number will not be changed. A single command or the first of a list of commands will appear on the same line as the global command. All lines of a multi-line list except the last line will be ended with a backslash; 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 is 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 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 is to mark every line that matches the given RE. Then, for every such line, that line will be written, the current line number will 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) can be input and will be executed. A newline character acts as a null command (causing no action to be taken on the current line); an & causes the reexecution 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. The final value of the current line number will be the value set by the last command successfully executed. (Note that the last command successfully executed will 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 will 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 writes a short message to standard output that explains the reason for the most recent ? notification. The current line number is unchanged.

 Help-mode Command

Synopsis:	H

The H command causes ed to enter a mode in which help messages (see the h command) will be written to standard output for all subsequent ? notifications. The H command alternatively will turn this mode on and off; it is initially off. If the help-mode is being turned on, the H command also will explain the previous ? notification, if there was one. The current line number is unchanged.

 Insert Command

Synopsis:	(.)i
	<text>
	.

The i command inserts the given text before the addressed line; . will be left at the last inserted line or, if there was none, at the addressed line. This command differs from the a command only in the placement of the input text. Address 0 is invalid for this command.

 Join Command

Synopsis:	(.,.+1)j

The j command joins contiguous lines by removing the appropriate newline characters. If exactly one address is given, this command will do nothing. If lines are joined, the current line number will be set to the address of the joined line; otherwise, the current line number is unchanged.

 Mark Command

Synopsis:	(.)kx

The m command marks the addressed line with name x, which must be a lower-case letter from the portable character set. The address 'x then refers to this line; the current line number is unchanged.

 List Command

Synopsis:	(.,.)l

The l command writes to standard output the addressed lines in a visually unambiguous form. The characters listed in the table in the XBD specification, File Format Notation  (\\, \a, \b, \f, \r, \t, \v) will be written as the corresponding escape sequence; the \n in that table is not applicable. Non-printable characters not in the table will 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-dependent.

Long lines will be folded, with the point of folding indicated by writing backslash/newline character; the length at which folding occurs is unspecified, but should be appropriate for the output device. The end of each line will be marked with a "$". An l command can be appended to any other command other than e, E, f, q, Q, r, w or !. The current line number will be set to the address of the last line written.

 Move Command

Synopsis:	(.,.)maddress

The m command repositions the addressed lines after the line addressed by address. Address 0 is valid for address and causes the addressed lines to be moved to the beginning of the buffer. It is an error if address address falls within the range of moved lines. The current line number will be set to the address of the last line moved.

 Number Command

Synopsis:	(.,.)n

The n command writes to standard output the addressed lines, preceding each line by its line number and a tab character; the current line number will 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 writes to standard output the addressed lines; the current line number will 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 causes ed to prompt with an asterisk (*) (or string, if -p is specified) for all subsequent commands. The P command alternatively turns this mode on and off; it is initially on if the -p option is specified, otherwise off. The current line number is unchanged.

 Quit Command

Synopsis:	q

The q command causes ed to exit. If the buffer has changed since the last time the entire buffer was written, the user will be warned, as described previously.

 Quit Without Checking Command

Synopsis:	Q

The Q command causes ed to exit without checking if changes have been made in the buffer since the last w command.

 Read Command

Synopsis:	($)r[file]

The r command reads in the file named by the pathname file and appends it after the addressed line. If no file argument is given, the currently remembered pathname, if any, will be used (see e and f commands). The currently remembered pathname will not be changed unless there is no remembered pathname. Address 0 is valid for r and causes 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 will be written to standard output in the following format:

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

 Substitute Command

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

The s command searches 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 will be set to the address of the last line on which a substitution occurred.

An ampersand (&) appearing in the replacement will 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, will 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 will be used as the replacement in the current substitute command; if there was no previous substitute command, the use of "%" in this manner is an error. The "%" loses 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 following character loses 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 character into it. The application must escape the newline character 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 will be set to the address of the last line on which a substitution is performed. If no substitution is performed, the current line number is unchanged. If a line is split, a substitution is considered to have been performed on each of the new lines for the purpose of determining the new current line number. A substitution is considered to have been performed even if the replacement string is identical to the string that it replaces.

The value of flags must be 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 will 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 will 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 will be written in the format specified for the p command.

 Copy Command

Synopsis:	(.,.)taddress

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

 Undo Command

Synopsis:	u

The u command nullifies 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 will be undone as a single change; if no changes were made by the global command (such as with g/RE the u command will have no effect. The current line number will 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 is equivalent to the global command g except that the lines that are marked during the first step will be those that do not match the RE.

 Interactive Global Not-matched Command

Synopsis:	(1,$)V/RE/

This command is equivalent to the interactive global command G except that the lines that are marked during the first step will be those that do not match the RE.

 Write Command

Synopsis:	(1,$)w[file]

The w command writes the addressed lines into the file named by the pathname file. The command will create the file, if it does not exist, or will replace the contents of the existing file. The currently remembered pathname will not be changed unless there is no remembered pathname. If no pathname is given, the currently remembered pathname, if any, will be used (see the e and f commands); the current line number is unchanged. If the command is successful, the number of bytes written will 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 will be taken to be a shell command line whose standard input will be the addressed lines. Such a shell command line will not be remembered as the current pathname. This usage of the write command with "!" will not be considered as a "last w command that wrote the entire buffer", as described previously; thus, this alone will 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 will be written to standard output in the following format:

"%d\n", <line number>

The current line number is unchanged by this command.

 Shell Escape Command

Synopsis:	!command

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

"!\n"

to standard output upon completion, unless the -s option is specified. The current line number is unchanged.

 Null Command

Synopsis:	(.+1)

An address alone on a line causes the addressed line to be written. A newline character alone is equivalent to .+1p. The current line number will be set to the address of the written line.

 EXIT STATUS

The following exit values are 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 will be flushed, and a new command read.

• If the standard input is a regular file, ed will terminate with a non-zero exit status.

 APPLICATION USAGE

Because of the extremely terse nature of the default error messages, the prudent script writer will begin the ed input commands with an H command, so that if any errors do occur at least some clue as to the cause will be made available.

 EXAMPLES

None.

 FUTURE DIRECTIONS

The obsolescent single-minus form may be withdrawn in a future issue. Applications should use the -s option.

The IEEE PASC 1003.2 Interpretations Committee has forwarded concerns about parts of this interface definition to the IEEE PASC Shell and Utilities Working Group which is identifying the corrections. A future revision of this specification will align with IEEE Std. 1003.2b when finalised.

 SEE ALSO

ex, sed, sh, vi.