189730b29SDavid Greenman 295e6217eSAndrew MooreThis version of ed(1) is not strictly POSIX compliant, as described in 395e6217eSAndrew Moorethe POSIX 1003.2 document. The following is a summary of the omissions, 495e6217eSAndrew Mooreextensions and possible deviations from POSIX 1003.2. 530154ac8SAndrew Moore 695e6217eSAndrew MooreOMISSIONS 795e6217eSAndrew Moore--------- 8ed9b87e3SSheldon Hearn1) For backwards compatibility, the POSIX rule that says a range of 995e6217eSAndrew Moore addresses cannot be used where only a single address is expected has 1095e6217eSAndrew Moore been relaxed. 1130154ac8SAndrew Moore 12ed9b87e3SSheldon Hearn2) To support the BSD `s' command (see extension [1] below), 1395e6217eSAndrew Moore substitution patterns cannot be delimited by numbers or the characters 1495e6217eSAndrew Moore `r', `g' and `p'. In contrast, POSIX specifies any character expect 1595e6217eSAndrew Moore space or newline can used as a delimiter. 1630154ac8SAndrew Moore 1795e6217eSAndrew MooreEXTENSIONS 1895e6217eSAndrew Moore---------- 1995e6217eSAndrew Moore1) BSD commands have been implemented wherever they do not conflict with 2095e6217eSAndrew Moore the POSIX standard. The BSD-ism's included are: 2195e6217eSAndrew Moore i) `s' (i.e., s[n][rgp]*) to repeat a previous substitution, 2295e6217eSAndrew Moore ii) `W' for appending text to an existing file, 2395e6217eSAndrew Moore iii) `wq' for exiting after a write, 2495e6217eSAndrew Moore iv) `z' for scrolling through the buffer, and 2595e6217eSAndrew Moore v) BSD line addressing syntax (i.e., `^' and `%') is recognized. 2630154ac8SAndrew Moore 27*d83db3fbSConrad Meyer2) The POSIX interactive global commands `G' and `V' are extended to 2895e6217eSAndrew Moore support multiple commands, including `a', `i' and `c'. The command 2995e6217eSAndrew Moore format is the same as for the global commands `g' and `v', i.e., one 3095e6217eSAndrew Moore command per line with each line, except for the last, ending in a 3195e6217eSAndrew Moore backslash (\). 3230154ac8SAndrew Moore 33*d83db3fbSConrad Meyer3) An extension to the POSIX file commands `E', `e', `r', `W' and `w' is 3495e6217eSAndrew Moore that <file> arguments are processed for backslash escapes, i.e., any 3595e6217eSAndrew Moore character preceded by a backslash is interpreted literally. If the 3695e6217eSAndrew Moore first unescaped character of a <file> argument is a bang (!), then the 3795e6217eSAndrew Moore rest of the line is interpreted as a shell command, and no escape 3895e6217eSAndrew Moore processing is performed by ed. 3930154ac8SAndrew Moore 40*d83db3fbSConrad Meyer4) For SunOS ed(1) compatibility, ed runs in restricted mode if invoked 4195e6217eSAndrew Moore as red. This limits editing of files in the local directory only and 4295e6217eSAndrew Moore prohibits shell commands. 4310ca1c6cSAndrew Moore 4495e6217eSAndrew MooreDEVIATIONS 4595e6217eSAndrew Moore---------- 4695e6217eSAndrew Moore1) Though ed is not a stream editor, it can be used to edit binary files. 4795e6217eSAndrew Moore To assist in binary editing, when a file containing at least one ASCII 4895e6217eSAndrew Moore NUL character is written, a newline is not appended if it did not 4995e6217eSAndrew Moore already contain one upon reading. In particular, reading /dev/null 5095e6217eSAndrew Moore prior to writing prevents appending a newline to a binary file. 5110ca1c6cSAndrew Moore 5295e6217eSAndrew Moore For example, to create a file with ed containing a single NUL character: 5395e6217eSAndrew Moore $ ed file 5495e6217eSAndrew Moore a 5595e6217eSAndrew Moore ^@ 5695e6217eSAndrew Moore . 5795e6217eSAndrew Moore r /dev/null 5895e6217eSAndrew Moore wq 5995e6217eSAndrew Moore 6095e6217eSAndrew Moore Similarly, to remove a newline from the end of binary `file': 6195e6217eSAndrew Moore $ ed file 6295e6217eSAndrew Moore r /dev/null 6395e6217eSAndrew Moore wq 6495e6217eSAndrew Moore 6595e6217eSAndrew Moore2) Since the behavior of `u' (undo) within a `g' (global) command list is 6695e6217eSAndrew Moore not specified by POSIX, it follows the behavior of the SunOS ed: 6795e6217eSAndrew Moore undo forces a global command list to be executed only once, rather than 68bf2fe08eSUlrich Spörlein for each line matching a global pattern. In addition, each instance of 6995e6217eSAndrew Moore `u' within a global command undoes all previous commands (including 7095e6217eSAndrew Moore undo's) in the command list. This seems the best way, since the 7195e6217eSAndrew Moore alternatives are either too complicated to implement or too confusing 7295e6217eSAndrew Moore to use. 7395e6217eSAndrew Moore 7495e6217eSAndrew Moore The global/undo combination is useful for masking errors that 7595e6217eSAndrew Moore would otherwise cause a script to fail. For instance, an ed script 76bf2fe08eSUlrich Spörlein to remove any occurrences of either `censor1' or `censor2' might be 7795e6217eSAndrew Moore written as: 7895e6217eSAndrew Moore ed - file <<EOF 7995e6217eSAndrew Moore 1g/.*/u\ 8095e6217eSAndrew Moore ,s/censor1//g\ 8195e6217eSAndrew Moore ,s/censor2//g 8295e6217eSAndrew Moore ... 8395e6217eSAndrew Moore 8495e6217eSAndrew Moore3) The `m' (move) command within a `g' command list also follows the SunOS 8510ca1c6cSAndrew Moore ed implementation: any moved lines are removed from the global command's 8610ca1c6cSAndrew Moore `active' list. 8795e6217eSAndrew Moore 8895e6217eSAndrew Moore4) If ed is invoked with a name argument prefixed by a bang (!), then the 8995e6217eSAndrew Moore remainder of the argument is interpreted as a shell command. To invoke 9095e6217eSAndrew Moore ed on a file whose name starts with bang, prefix the name with a 9195e6217eSAndrew Moore backslash. 92