Say I want to match either sh or /sh. I've tried to change the order of the two characters like this [/^]sh$, but this will match /sh or ^sh, "the caret character" rather than "the beginning of the line". Escaping the ^ with \ has the same result. So is it possible to do this using the brackets syntax?
PS: I'm using grep in ADB shell, the grep here may be a little different than in standard *nix systems.
Regarding is it possible to do this using the brackets syntax - sure, there's various characters you could put inside a bracket expression but it's not obvious why you'd want to. You should just use:
grep -E '^/?sh'
for this as it means exactly what you say you want - start of line (^) then optional / then sh so it'll match sh or /sh and nothing else.
Regarding:
I'm using grep in ADB shell, the grep here may be a little different than in standard *nix systems.
If your grep is different enough that it doesn't support EREs then use awk instead:
awk '/^\/?sh/'
or (and here's where a bracket expression could be used usefully):
awk '/^[/]?sh/'
Either of those will work using any awk in any shell on every Unix box.