Shell/Bash shortcut for bulk renaming of files in a folder

Question

Is there a shortcut in Shell/Bash that can rename all the files in a folder based on a regex or some other criteria. What I am looking for here is in my folder documents, that has let's say a 100 text files with the following naming convention:

<longdocumentidentifier>-doc-<counter>.txt.

I need to rename all the files with the above given convention to just:

doc-<counter>.txt

Is there a one-liner that can help me with the above?

Answer 1

I would suggest something like this:

for i in *-doc-*.txt; do mv "$i" "${i/*-doc-/doc-}"; done

${i/*-doc-/doc-} replaces the first occurrence of *-doc- with doc-.

If you need to do more than one replacement (see comment number 1), you need to use the ${var//Pattern/Replacement} variant. If you need to replace the beginning of the name you need to use ${var/#Pattern/Replacement}, if you need to replace the end (ie: the extension) you need to use the ${var/%Pattern/Replacement} form.

See Shell Parameter Expansion for more details. This expansion is bash specific.