Shell Programming and Scripting

so I have about 30k jpg files that I need to rename in one hit. The current filename format is:

Code:

x_surname_firstname_y_20141115_OS_(z)

where x, y and z are numbers of various lengths

the new filename format needs to be

Code:

surname_firstname_y_OS_(z)

So I basically need to remove the first number x with the adjacent underscore and the datestamp after y

Would be very grateful for some help - thanks

Hmmm!

I have tried various bits of code via google all of which used sed but I don't know enough to change the code to suit my needs

It's a good idea to have a backup of the files you want to rename *before* you attempt to perform the mass rename process. Just in case something goes wrong.

Try this to see if the mv commands are being built as expected:

Code:

ls *_*_*_*_*_*_* | awk -F_ '{ printf "mv \"%s\" \"%s_%s_%s_%s_%s\"\n",
$0, $2, $3, $4, $6, $7 }'

Run this to perform the actual mass rename process (be patient):

Code:

ls *_*_*_*_*_*_* | awk -F_ '{ printf "mv \"%s\" \"%s_%s_%s_%s_%s\"\n",
$0, $2, $3, $4, $6, $7 }' | sh

Hmmm!

With 30k files even if x, y, and z are all single digit numbers, the arg list for the ls command suggested by junior-helper will be over a megabyte. On many systems that will be too big to exec. I don't see any need for awk or perl for this; it can easily be done entirely in the shell:

Code:

#!/bin/ksh
for i in *_*_*_*_*_*_*
do	printf '%s\n' "$i" | { IFS="_" read x s f y x o z
		echo mv "$i" "${s}_${f}_${y}_${o}_$z"
	}
done

To actually move the files instead of just showing what commands it produces, take out the echo shown in red after you verify that the mv commands produced by this script will do what you want.

This will work with any POSIX conforming shell (such as ksh and bash) no matter how many files are present matching the pattern.

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Oops. POSIX allows the elements of a pipeline to be executed in separate subshell environments. The above will work with any POSIX shell; the original script provided before this edit works in ksh, but not bash.

Hmmm!