Unix CLI script to rename folders using their pre-existing names - regex

Question

I have a directory with folder structure as follows:
-- DATA -- ABD 1231345 -- 01-08-12 // date in mm-dd-yy format
-- 03-09-12
-- 06-11-12
-- DEF 4859480 -- 02-10-12
-- 05-10-12
-- 07-10-12
I would like to batch rename this DATA folder as follows
-- DATA -- ABD 1231345 -- 2012_01_08 // date in yyyy_mm_dd format with underscore
-- 2012_03_09
-- 2012_06_11
-- DEF 4859480 -- 2012_02_10
-- 2012_05_10
-- 2012_07_10
Do you have a suggestion on how to accomplish using command line on Mac OSX / unix?

Answer 1

You could use a for loop and awk, parsing each file-name into your specified format and then mv to rename the original to the new name:
for dir in DATA/*; do \
pushd "$dir"; # change directory \
for file in *; do \
path=`echo $file | awk -F- '{print "20"$3"_"$1"_"$2}'`; \
mv $file $path; # "rename" the file \
done; \
popd; # restore original directory \
done;
This can be executed in folder above DATA. If you want to execute it directly in DATA, update the first loop to read for dir in *; do instead of DATA/*. It tells awk to use the - as the delimiter (instead of whitespace), and then reconstructs a string from "mm-dd-yy" to "20yy_mm_dd".
Using pushd and popd will enable the script to change the current directory to each subdirectory inside DATA (pushd) and then, after moving all necessary files will change back to the original (popd). Doing this will save you a lot of parsing-effort trying to save directory paths / etc.

Answer 2

You could use string manipulations and arrays to do that with bash only.
Something like:
for f in * ; do
parts=(${f//-/ })
mv "$f" "20${parts[2]}_${parts[1]}_${parts[0]}"
done
Search this site for various options to recurse into directories e.g.:
Shell script to traverse directories

Answer 3

Use the date command to convert the file name:
$ date -j -f %m-%d-%y 01-08-12 +%Y_%m_%d
2012_01_08
Getting to the files is a little tricker. We'll just switch directories to avoid dealing with long file paths.
for d in DATA; do
pushd "$d"
for f in *; do
new_f=$(date -j -f %m-%d-%y $f +%Y_%m_%d)
mv "$f" "$new_f"
done
popd
done

Answer 4

This site gives a good snippet
for i in *.avi; do j=`echo $i | sed 's/(\d{2})-(\d{2})-(\d{2})/20\3_\1_\2/g'`; mv "$i" "$j"; done