#!/bin/bash
X=ABC
echo "$Xabc"

THis gives no output. What went wrong ? The answer is that the shell thought that we were asking for the variable Xabc, which is uninitialised. The way to deal with this is to put braces around X to seperate it from the other characters. The following gives the desired result:
#!/bin/bash
X=ABC
echo "${X}abc"

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I think that it will clear your doubt.
still you are not getting ...pls give full details so that we can give a solution of same

Thanks
Ckanth