As a concrete example, let us consider the problem that we often have
uploading pictures to certain sites (e.g. ebay). The photos from our
camera all have .JPG extension. However, when we attempt to locate
those pictures from some web sites, no photos are found. This is
because something in the chain of events only lower case extensions,
such as .jpg, are allowed.
The task is to change all files in a directory
(e.g. /DATA01/Pictures/EBAY/2010-09-10) from upper case
(.JPG) to lower case (.jpg) extensions.
cd /DATA01/Pictures/EBAY/2010-09-10 for i in *.JPG; do mv "$i" "${i/.JPG}".jpg; done
Simple.
If the task is a bit more complex will do well to use another standard Unix
tool with regular expression capability (such as sed). For example, if
we have files with a date in the name (e.g. 20101210) and want to change
the date (e.g. to 20110119), then here is solution.
for i in *20101210*; do j=`echo $i | sed s/20101210/20110119/`; mv $i $j; done
Still simple.
