POSIX revision 1.5
1 This version of ed is not strictly POSIX compliant, as described in the 2 POSIX 1003.2 Draft 11.2 document. BSD commands have been implemented 3 wherever they do not conflict with the POSIX standard. For backwards 4 compatibility, the POSIX rule that says a range of addresses cannot be 5 used where only a single address is expected has been relaxed. 6 7 The BSD commands included are: 8 1) `s' (i.e., s[rgp]*) to repeat a previous substitution, 9 2) `W' for appending text to an existing file, 10 3) `wq' for exiting after a write, and 11 4) `z' for scrolling through the buffer. 12 BSD line addressing syntax (i.e., `^' and `%'). is also recognized. 13 14 The POSIX interactive global commands `G' and `V' are extended to support 15 multiple commands, including `a', `i' and `c'. The command format is the 16 same as for the global commands `g' and `v', i.e., one command per line 17 with each line, except for the last, ending in a backslash (\). 18 19 If crypt is available, files can be read and written using DES encryption. 20 The `x' command prompts the user to enter a key used for encrypting/ 21 decrypting subsequent reads and writes. If only a newline is entered as 22 the key, then encryption is disabled. Otherwise, a key is read in the 23 same manner as a password entry. The key remains in effect until 24 encryption is disabled. For more information on the encryption algorithm, 25 see the bdes(1) man page. Encryption/decryption should be fully compatible 26 with SunOS DES. 27 28 An extension to the POSIX file commands `E', `e', `r', `W' and `w' is that 29 <file> arguments are processed for backslash escapes, i.e., any character 30 preceded by a backslash is interpreted literally. If the first unescaped 31 character of a <file> argument is a bang (!), then the rest of the line 32 is interpreted as a shell command, and no escape processing is performed 33 by ed. 34 35 The vi editor's bang command syntax is supported, i.e., 36 (addr1,addr2) !<shell-cmd> replaces the addressed lines with the output of 37 the command <shell-cmd>. 38 [rwe] !! reads/writes/edits the previous !<shell-cmd>. 39 40 If ed is invoked with a name argument prefixed by a bang, then the 41 remainder of the argument is interpreted as a shell command. To invoke 42 ed on a file whose name starts with bang, prefix the name with a backslash. 43 44 ed runs in restricted mode if invoked as red. This limits editing of 45 files in the local directory only and prohibits !<shell-cmd> commands. 46 47 Though ed is not a binary editor, it can be used (if painfully) to edit 48 binary files. To assist in binary editing, when a file containing at 49 least one ASCII NUL character is written, a newline is not appended 50 if it did not already contain one upon reading. 51 52 Since the behavior of `u' (undo) within a `g' (global) command list is 53 not specified by POSIX D11/2, it follows the behavior of the SunOS ed 54 (this is the best way, I think, in that the alternatives are either too 55 complicated to implement or too confusing to use): undo forces a global 56 command list to be executed only once, rather than for each line matching 57 a global pattern. In addtion, each instance of `u' within a global command 58 undoes all previous commands (including undo's) in the command list. 59 60 The `m' (move) command within a `g' command list also follows the SunOS 61 ed implementation: any moved lines are removed from the global command's 62 `active' list. 63
Indexes created Mon Sep 07 00:24:45 UTC 2026