32v 1m ed
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ED(1) UNIX Programmer's Manual ED(1)
ed - text editor
ed [ - ] [ -x ] [ name ]
_E_d is the standard text editor.
If a _n_a_m_e argument is given, _e_d simulates an _e command (see below) on the named file; that is to say, the file is read into _e_d'_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.
_E_d 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 _b_u_f_f_e_r.
Commands to _e_d have a simple and regular structure: zero or more _a_d_d_r_e_s_s_e_s followed by a single character _c_o_m_m_a_n_d, pos- sibly 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 _e_d is accepting text, it is said to be in _i_n_p_u_t _m_o_d_e. In this mode, no commands are recognized; all input is merely col- lected. Input mode is left by typing a period `.' alone at the beginning of a line.
_E_d supports a limited form of _r_e_g_u_l_a_r _e_x_p_r_e_s_s_i_o_n notation. A regular expression specifies a set of strings of charac- ters. A member of this set of strings is said to be _m_a_t_c_h_e_d by the regular expression. In the following specification for regular expressions the word `character' means any char- acter but newline.
1. Any character except a special character matches itself. Special 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 character.
4. A nonempty string _s bracketed [_s] (or [^_s]) matches any character 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 sequence of 0 or more matches of the regular expres- sion.
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 reg- ular expression 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 fol- lowed by $), is constrained to matches that begin at the left (or end at the right) end of a line.
10. A regular expression of form 1-9 picks out the longest among the leftmost matches in a line.
11. An empty regular expression stands for a copy of the last regular expression encountered.
Regular expressions are used in addresses to specify lines and in one command (see _s below) to specify a portion of a line which is to be replaced. If it is desired to use one of the regular expression metacharacters as an ordinary character, that character may be preceded by `\'. This also applies to the character bounding the regular expression (often `/') and to `\' itself.
To understand addressing in _e_d it is necessary to know that at any time there is a _c_u_r_r_e_n_t _l_i_n_e. Generally speaking, the current line is the last line affected by a command; how- ever, the exact effect on the current line is discussed under the description of the command. Addresses are con- structed as follows.
1. The character `.' addresses the current line.
2. The character `$' 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 described 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 expression. 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 `-' followed by a decimal number specifies that address plus (resp. minus) the indicated number of lines. The plus sign may be omitted.
8. If an address begins with `+' or `-' the addition or subtraction is taken with respect to the current line; e.g. `-5' is understood to mean `.-5'.
9. If an address ends with `+' or `-', then 1 is added (resp. subtracted). As a consequence of this rule and rule 8, the address `-' refers to the line before the current line. Moreover, trailing `+' and `-' charac- ters 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 require no addresses regard the presence of an address as an error. Commands which accept one or two addresses assume default addresses when insufficient are given. If more addresses are given than such a command requires, the last one or two (depending on what is accepted) are used.
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 interpreted. This feature can be used to determine the starting line for for- ward and backward searches (`/', `?'). The second address of any two-address sequence must correspond to a line fol- lowing the line corresponding to the first address.
In the following list of _e_d 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 com- mand to appear 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 respectively in the way discussed below.
(.)a <text> . 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 <text> . The change command deletes the addressed lines, then accepts input text which replaces these lines. `.' is left at the last line input; 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 current 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 remembered name is used.
E filename This command is the same as _e, except that no diagnos- tic 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,$)g/regular expression/command list In the global command, the first step is to mark every line which matches the given regular expression. Then for every such line, the given command list is executed with `.' initially set to that line. A single command or the first of multiple commands appears on the same line with the global command. All lines of a multi- line list except the last line must be ended with `\'. _A, _i, and _c commands and associated input are permit- ted; the `.' terminating input mode may be omitted if it would be on the last line of the command list. The commands _g and _v are not permitted in the command list.
<text> . This command inserts the given text before the addressed line. `.' is left at the last line input, or, if there were none, at the line before the addressed line. This command differs from the _a com- mand only in the placement of the text.
(., .+1)j This command joins the addressed lines into a single line; intermediate newlines simply disappear. `.' is left at the resulting line.
( . )k_x The mark command marks the addressed line with name _x, which must be a lower-case letter. The address form `'_x' then addresses this line.
(., .)l The list command prints the addressed lines in an unam- biguous way: non-graphic characters are printed in two-digit octal, and long lines are folded. The _l com- mand may be placed on the same line after any non-i/o command.
(., .)m_a The move command repositions the addressed lines after the line addressed by _a. The last of the moved lines becomes the current line.
(., .)p The print command prints the addressed lines. `.' is left at the last line printed. The _p command may be placed on the same line after any non-i/o command.
(., .)P This command is a synonym for _p.
q The quit command causes _e_d to exit. No automatic write of a file is done.
Q This command is the same as _q, except that no diagnos- tic results when no _w has been given since the last buffer alteration.
($)r filename The read command reads in the given file after the addressed line. If no file name is given, the remem- bered file name, if any, is used (see _e and _f com- mands). 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 occurrence of the specified regular expression. On each line in which a match is found, all matched strings are replaced by the replacement 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 reg- ular 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 left.
Lines may be split by substituting new-line characters into them. The new-line in the replacement string must be escaped by preceding it by `\'.
(., .)t_a 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 made.
(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 _e_x_c_e_p_t those matching the regular expression.
(1, $)w filename The write command writes the addressed lines onto the given file. If the file does not exist, it is created mode 666 (readable and writable by everyone). The file name is remembered if there was no remembered file name already. If no file name is given, the remembered file name, if any, is used (see _e and _f commands). `.' is unchanged. If the command is successful, the number of characters written is printed.
(1,$)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 _c_r_y_p_t(1). An explicitly empty key turns off encryption.
($)= 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 _s_h(1) to be interpreted as a command. `.' is unchanged.
(.+1)<newline> 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, _e_d prints a `?' and returns to its command level.
Some size limitations: 512 characters per line, 256 charac- ters 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, _e_d discards ASCII NUL characters and all characters after the last newline. It refuses to read files containing non-ASCII characters.
/tmp/e* ed.hup: work is saved here if terminal hangs up
B. W. Kernighan, _A _T_u_t_o_r_i_a_l _I_n_t_r_o_d_u_c_t_i_o_n _t_o _t_h_e _E_D _T_e_x_t _E_d_i_- _t_o_r B. W. Kernighan, _A_d_v_a_n_c_e_d _e_d_i_t_i_n_g _o_n _U_N_I_X 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 buffer 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 _e_d.