UNIX for Dummies Questions & Answers

Hi, I'm relatively new to unix, and would like to change the following files in a particular directory. The files have names like:

M10_90_Phcn402_3F.ab1
M10_94_Sput402_3F.ab1
M11_92_Abrg402_3R.ab1
M10_91_Cdel402_3F.ab1
M11_90_Phcn402_3R.ab1
M12_84_Sput402_3R.ab1
M10_93_Ehdr402_3F.ab1
M11_71_Cdel402_3R.ab1
M12_95_Epic402_3R.ab1

I would like to remove the first 7 characters of each file. For instance, in the first one, I would like M10_90_ to be removed, so the file name becomes Phcn402_3F.ab1

I have been playing with:

for x in M1*;do mv $x ${x/nnn/};done

I'm not sure what the correct expression is to remove the first 7 characters (not sure what to put in place of "nnn"). Is there a fast way to do this, or is there a different way to do this, maybe with "rename"?

Thanks

Code:

#!/bin/ksh
for i in M1*
do
   echo mv "${i}" "${i##???????}"
done

Once satisfied with the echo-ed results, remove the 'echo'

To remove up to and including the second underscore:

Code:

mv "$x" "${x#*_*_}"

Thanks, this is really useful!

How about rename ?

Code:

rename 's/(.){7}//' *.ab1