linux - Bash / Substring of a string

Question

I try to find a substring of a string.

If I have the string try-30/16, I want to get the 30 string.

so I wrote the next:

n=${"'$b'":'-':'/'}

where $b is a variable I assign before this command. It gives the next:

bad substitution.

How I can do it?

Answer 1

尝试这个。

b="try-30/16"
n=${b##*-}
n=${n%%/*}
echo $n

Answer 2

你也可以这样做：

[[ $b =~ [^-]+-([0-9]+) ]] && echo "${BASH_REMATCH[1]}"

输出：

30

现场演示：http: //ideone.com/bKHGcS

Answer 3

$ n=${b%/*}
$ n=${n#*-}
$ echo $n
30