7 # 上边的每个echo都打印出相同的结果.
expr match "$string" '.*\($substring\)'
从$string的结尾提取$substring, $substring是正则表达式.
expr "$string" : '.*\($substring\)'
从$string的结尾提取$substring, $substring是正则表达式.
1 stringZ=abcABC123ABCabc
2 # ======
3
4 echo `expr match "$stringZ" '.*\([A-C][A-C][A-C][a-c]*\)'` # ABCabc
5 echo `expr "$stringZ" : '.*\(......\)'` # ABCabc