Is there a preference in Textwrangler to redefine a tab as 4 spaces? In Vim this is set expandtab in the vimrc, but I don't know how to set it in TW besides clicking "Detab" when I'm done editing the document.
Thanks, Kevin
Go to "Preferences" -> "Editor Defaults" -> "Auto-expand tabs," and then set tabs to 4 spaces. Then restart TextWrangler for changes to take place.
For docs that already exist you have to hit the "Text options" button in the top of the editor window of the open document. It's the button that looks like a "T" with a light switch next to it. In that drop down there is the "auto-expand tabs" there as well.
in version 4.5.5, there is 'Text -> Detab...', which pops up a requester for how many space per tab, preset for 4.
Go to Edit -> Text Options and tick Auto-expand tabs. This will make all the new tabs to change to spaces.
To change all current tabs to spaces as well, go to Text -> Detab and hit Detab.
Hope that helps!
For Mac, another easy way to check and enable "Auto-expand tabs" is to hit the gear button on top left.
You can also use "Normalize Options..." to set the text options of an already-open document to whatever you have set in your Preferences. This is useful for dealing with pre-existing code.
来源：https://stackoverflow.com/questions/5750361/auto-convert-tab-to-4-spaces-in-textwrangler