Hi,
You're welcome. First, note that the commands:

Code:

set -xv
find . -name '*DTISiemensTCless*.bv[ea][cl]' |
while read -r path
do	dir="${path%/*}"
	file="${path##*/}"
	subjectnumber="${file%%DTI*}"
	ext="${file##*.}"
	echo mv "$path" "$dir/${subjectnumber}DTI.$ext"
done
set +xv

will make ABSOLUTELY NO CHANGES to any files on your system unless you remove the echo. Let me expand a little on what I said earlier: There is NO WAY to learn how to run shell commands and write shell scripts other than to run shell commands and write and run shell scripts. Run the above commands, go through the trace output line by line (referring to the bash man page) if you don't understand how the various parameter expansions are working when it is extracting the directory (dir), filename (file), the subject number (subjectnumber), and the filename extension (ext) from the pathnames (path) found by the find command, and look at the mv command that is printed by the echo command.

And, for the commands:

Code:

[bash]mv *.bvec bvecs[/bash]
[bash]mv *.bval bvals[/bash]

... I repeat: You have to run shell commands to learn what shell commands do!

And, if you try running those commands you are very likely to get a diagnostic message saying that there is no command named [bash]mv unless there is a utility named amv, bmv, hmv, smv, or [bash]mv on your system. Once you practice running commands and learn how pathname expansions work, you'll understand why I gave that list of utility names AND you'll recognize that [bash] and [/bash] are tags used in the book you were looking at indicating that stuff between those tags is a command to be given to the bash shell command language interpreter; not part of the text of the commands themselves.

Note however, that running a mv command will actually move files. So do this in a directory with test files you have set up with matching names; do not try this in a directory where you have files with names ending in .bvec or .bval and directories named bvecs and bvals unless you actually want to move all of the files with names ending in .bval to the directory named bvals and want to move all of the files with names ending in .bvec to the directory named bvecs.

If those directories don't exist, what happens will vary depending on how many files match those filename patterns. Why don't you look at the mv man page and tell me what will happen in each of the following cases when you run the command:

Code:

mv *.bvec bvecs

and: