Hi,

I have the input file having data as follow:
file1.txt
001 aaa_1:abcd
002 bbb_2:abcd

I want output as,
001xabcd
002xabcd

Here iam trying to replace "{1 space}{alphanumeric string with underscore}{:}" with characrter "x".
I tried to achieve this using sed;but Iam not getting this correctly.

Thanks in advance.