In .htaccess:

<Files myfile.php>
AuthType Basic
AuthName "Authentication Required"
AuthUserFile /path/to/.htpasswd
Require valid-user
</Files>

Getting a single file (with convenience jQuery event handler)

$('#open #chooseFile').change(function(e){
    var fileList = e.target.files;
    // get the one and only file
    var file = fileList[0];
    // further process file content...
    var reader = new FileReader();
    reader.readAsText(file, "text/plain");      
    reader.onload = localLoaded;
    reader.onerror = localError;
    // ...
});

Getting multiple files:

$('#open #chooseFile').change(function(e){
    var fileList = e.target.files;
    // loop over the files

    for (var i=0, file; file=fileList[i]; i++) {
        var reader = new FileReader();
        reader.readAsText(file, "text/plain");      
        reader.onload = localLoaded;
        reader.onerror = localError;
        // ...
    }
});

Ok, here's a challenge. Say, you have a massive, 11 Gigabyte text file. The first two lines are the header files, unfortunately the header on line 2 is slightly wrong: Instead of 'Done' it should say 'Status:Done'. (Hit: 'Done' is the first occurrence of that string in that line)

Any Ideas?

• split and the cat? Could not figure out to split it in uneven files, i.e. the first 2 lines and the rest...
• vi? Seems to open, but bulks when saving it.

[Update]

sed seems to be the tool for this job. sed '2 s/Done/Status:Done/' input.txt > output.txt

Took about 7 minutes on my machine... Any better ideas still very much appreciated.

[Update 2: How to insert a tab with sed]

Inserting a tab with sed turned out to be more resilient than expected. Neither an escaped tab (\t) not a double-escaped tab (\t) seemed to do the trick. On bash it is necessary to drop out of sed and print the tab (\011) directly. 27 in the following statement means of course line 27.

sed '27 s/Done/Status:Done'"$(printf '\011')"'After Tab/' in.txt > out.txt

writetofile API Reference

- (BOOL)writeToFile:(NSString *)path 
         atomically:(BOOL)useAuxiliaryFile;

Works with:

NSDictionary
NSArray
NSData
NSString

For more complicated purposes, NSOutputStream might be the best option, but for simply writing a date or even XML this might be the simplest and fasted way.