changing the names of files within a directory [duplicate]

Question

I have few files under a particular directory. These are the files

idex.1.ebwt  idex.2.ebwt  idex.3.ebwt  idex.4.ebwt  idex.rev.1.ebwt  idex.rev.2.ebwt

I want to change the names of the file from idex to index keeping the rest of the name same. Basically I want to replace idex with index

Any one line command?

Answer 1

You could do this with a simple for-loop and some shell magic:

for file in idex.*; do
    mv "$file" "index${file#idex}"
done

Yes, you could also put this into one line. ;)

${var#pattern} evaluates to $var with a leading pattern removed (where pattern is a glob(7) pattern). There exist four variants of this (POSIX compliant):

1. ${var#pattern} evaluates to $var with a leading pattern removed (non-greedy).
2. ${var##pattern} evaluates to $var with a leading pattern removed (greedy).
3. ${var%pattern} evaluates to $var with a trailing pattern removed (non-greedy).
4. ${var%%pattern} evaluates to $var with a trailing pattern removed (greedy).

Difference to non-greedy and greedy is that if you have for example $var set to foo.bar.baz, ${var%.*} will evaluate to foo.bar, but ${var%%.*} will evaluate to foo. This is because ${var%.*} will search for the shortest pattern matching .* (thus from last . to end), where ${var%%.*} will search for the longest one (thus from first . to end).

You can help yourself memorizing which version are the non-greedy and the greedy ones simply with memorizing that the longer (# resp. % twice) search for a longer match.

Answer 2

If you're using a major linux distribution or have the standard util-linux package installed, this one-liner code should do what you want.

rename idex index idex*