Thanks all!
The following works ok in bash shell:
Code:
[river@localhost ~]$ [[ "123" =~ [[:digit:]]{3} ]] && echo "ok" || echo "error"
ok
[river@localhost ~]$ [[ "123" =~ [0-9]{3} ]] && echo "ok" || echo "error"
ok
The following is what I want:
Code:
[river@localhost ~]$ reg='\b[0-9]{3}\b'
[river@localhost ~]$ [[ "123" =~ $reg ]] && echo "ok" || echo "error"
ok
However, why I must put the expression in a variable .
Code:
[river@localhost ~]$ [[ "123" =~ \b[0-9]{3}\b ]] && echo "ok" || echo "error"
error
