1 Quick Tutorial

So, really, you just are in a hurry to use recode, and do not feel like studying this manual? Even reading this paragraph slows you down? We might have a problem, as you will have to do some guess work, and might not become very proficient unless you have a very solid intuition….

Let me use here, as a quick tutorial, an actual reply of mine to a recode user, who writes:

My situation is this—I occasionally get email with special characters in it. Sometimes this mail is from a user using IBM software and sometimes it is a user using Mac software. I myself am on a SPARC Solaris machine.

Your situation is similar to mine, except that I often receive email needing recoding, that is, much more than occasionally! The usual recodings I do are Mac to Latin-1, IBM page codes to Latin-1, Easy-French to Latin-1, remove Quoted-Printable, remove Base64. These are so frequent that I made myself a few two-keystroke Emacs commands to filter the Emacs region. This is very convenient for me. I also resort to many other email conversions, yet more rarely than the frequent cases above.

It seems like this should be doable using recode. However, when I try something like ‘grecode mac macfile.txt’ I get nothing out—no error, no output, nothing.

Presuming you are using some recent version of recode, the command:

recode mac macfile.txt

is a request for recoding macfile.txt over itself, overwriting the original, from Macintosh usual character code and Macintosh end of lines, to Latin-1 and Unix end of lines. This is overwrite mode. If you want to use recode as a filter, which is probably what you need, rather do:

recode mac

and give your Macintosh file as standard input, you’ll get the Latin-1 file on standard output. The above command is an abbreviation for any of:

recode mac..
recode mac..l1
recode mac..Latin-1
recode mac/CR..Latin-1/
recode Macintosh..ISO_8859-1
recode Macintosh/CR..ISO_8859-1/

That is, a CR surface, encoding newlines with ASCII CR, is first to be removed (this is a default surface for ‘mac’), then the Macintosh charset is converted to Latin-1 and no surface is added to the result (there is no default surface for ‘l1’). If you want ‘mac’ code converted, but you know that newlines are already coded the Unix way, just do:

recode mac/

the slash then overriding the default surface with empty, that is, none. Here are other easy recipes:

recode pc          to filter IBM-PC code and CR-LF (default) to Latin-1
recode pc/         to filter IBM-PC code to Latin-1
recode 850         to filter code page 850 and CR-LF (default) to Latin-1
recode 850/        to filter code page 850 to Latin-1
recode /qp         to remove quoted printable

The last one is indeed equivalent to any of:

recode /qp..
recode l1/qp..l1/
recode ISO_8859-1/Quoted-Printable..ISO_8859-1/

Here are some reverse recipes:

recode ..mac       to filter Latin-1 to Macintosh code and CR (default)
recode ..mac/      to filter Latin-1 to Macintosh code
recode ..pc        to filter Latin-1 to IBM-PC code and CR-LF (default)
recode ..pc/       to filter Latin-1 to IBM-PC code
recode ..850       to filter Latin-1 to code page 850 and CR-LF (default)
recode ..850/      to filter Latin-1 to code page 850
recode ../qp       to force quoted printable

In all the above calls, replace ‘recode’ by ‘recode -f’ if you want to proceed despite recoding errors. If you do not use ‘-f’ and there is an error, the recoding output will be interrupted after first error in filter mode, or the file will not be replaced by a recoded copy in overwrite mode.

You may use ‘recode -l’ to get a list of available charsets and surfaces, and ‘recode --help’ to get a quick summary of options. The above output is meant for those having already read this manual, so let me dare a suggestion: why could not you find a few more minutes in your schedule to peek further down, right into the following chapters!