Shell Programming and Scripting

Having problem in using the grep command to select all possible combinations a number in a file. Example: 123, I would like to grep the numbers 123,132,213,231,312 and 321.

have your tried grep [123][123][123]?

Sorry that I was not very clear. What I'm trying to do is create a grep script where I can enter any 3 digit number and the script grep the file to get all the possible combinations of the 3 digit number. There are up to six possible combinations for any 3 digit number.
I do not want to key all 6 possible combination with each grep or egrep search.