Have files of the sort 3p1522015.dgn and need to have them renamed to 152201.dgn. Essentially dropping the 1st 2 characters and the last. I'm relatively new to UNIX and uncertain of where to start. I hope this provides enough detail.

Thanks

Easy to do using bash shell

newfilename=${filename:2:6}.dgn

don't understand this line ? is this built into bash as i don't see a command...? even thought that was regular expression!

thanx in advance!

if your filenames are of fixed length and you just need to remove the first two chars and last char and rename it , then this might help,


team$ filename="3p1522015.dgn"
team$ basename $filename
3p1522015.dgn
team$ basename $filename | cut -c 3-8
152201
team$ newfilename=`basename $filename | cut -c 3-8`.dgn
team$ echo $newfilename
152201.dgn
team$ unset filename newfilename
team$

Yes, this is bash syntax. It takes characters 2 through 6 of filename, appends ".dgn" and assigns it to newfilename. Google for bash regular expressions and you wish find a number of tutorials on the subject.

it is worthy to learn such features of bash, at some situation bash can perform some operation very easily and efficiently compare to sed and awk.specially when you write a bash script you would prefer to use a bash inbuilt command than invoking some other tool or command


Rakesh UV