Shell tab-completion and other helpful command-line tricks

Nils Kassube kassube at
Sat Jan 24 08:12:41 UTC 2009

Paul Rumelhart wrote:
> One of the best time savers when in a bash shell is it's feature called
> "tab completion".


> Some examples:
> Filenames:

There are two things you didn't mention.

1. If a file name contains special characters the command completion uses 
backslashes as escape character in front of the special characters. E.g. 
if you have a file name "isn't this funny?.txt" and you type

ls is<tab>

the result of the command completion is this:

ls isn\'t\ this\ funny\?.txt

2. The command completion doesn't work within quotes. Using the file name 
above it wouldn't work if I type this:

ls "is<tab>

So if you want to use command completion, don't use quotes.

> Command-line switches - if you forget which switches ("--something") a
> particular command takes, you can type the command followed by a space
> and "--" and then press the tab key twice to get a list of possible
> choices (for example "ls --<tab><tab>" will show you all of the
> switches that ls will accept.

Did you try that? It doesn't work here. Or is there some special addon to 
bash needed to make it work? If you don't know the switches, use 
the --help option. Many commands answer with a usage message.

> There are lots of others I keep finding.  Many commands that have a
> choice of arguments work to some degree.  For example, typing "alias
> <tab><tab>" will show you which aliases you have currently defined.

Doesn't work either. But if you want to get a list of your aliases just 
try the alias command without parameters.


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