how to use * in sh string comparison -

how correctly use * in sh? tried googling couldn't find anything. following echo ture. why that?

file="test test"  if [ "$file" != "te"* ]      echo true  else     echo false  fi 

to avoid potential problems, when using posix shell, should consider using old expr regex or match expressions. choices are:

#!/bin/sh  file="test test"  if [ $(expr "$file" : "te.*") -gt 0 ]     echo true else     echo false fi 

or

if [ $(expr substr "$file" 1 2) = "te" ]     echo true else     echo false fi 

not elegant, proper tools shell. short explanation of each , expr syntax each is:

string : regularexp          : returns length of string if both sides match,                                 returns 0 otherwise match string regularexp      : same previous 1 substr string start length   : returns substring of string starting                                 start , consisting of length characters