Need a REGEX to increment the file number of a pdf file

[Marcus Aurelius]

Don't use '019' but '19'. When you write '019' it is assumesd to be a number in octal notation (in which '9' isn't a valid digit)....

May I point out that the code by my esteemed co-posters requires you to first spot any duplicates, while my suggestion can be applied blindly?

OK, thank you, that worked. I also see the wisdom of using your program as it reorders from start to finish, thanks for pointing that out. I'm very new to any programming so I started with the easiest to read. I have a question about reading your code:

count=$(( $count + 1 ))
I understand increments and saves count...then:

count0="000$count"
What's here, count0 is assigned 0001?

renumbered="${count0: -3}_${file#???_}"
THEN, get a little mixed up. Takes file number whatever say 256_ (puts in $)....then count0 (or 0001): -3 ...this lost me
so what is ${count0: -3} saying exactly?

[[ "$file" != "$renumbered" ]] && echo mv -v "$file" "$renumbered"
I think I understand this: (& finally pop out the echo when test succeeds)

OK, other than my lack of coding knowledge I think you found the best solution to my issue.
Thanks again.

[schragge]

$count0 just pads $count on the left with 000, then ${count0: -3} takes only the three rightmost characters of it. That gives

$count	$count0	${count0: -3}
1	0001	001
23	00023	023
456	000456	456

[Marcus Aurelius]

Thank you very much, and I completely understand now.

[Vaphell]

about that zero forcing octal system where 9 is illegal: you can easily circumvent that issue and force decimal system

$ x=019
$ printf "%03d\n" $(( x+5 ))  # pad with 0s to 3digits
bash: 019: value too great for base (error token is "019")
$ printf "%03d\n" $(( 10#$x+5 ))
024

[Marcus Aurelius]

.........Since the upgrade of the forum there's still a problem with the option to mark the threads as solved in the Thread Tools combo. The workaround is to edit the thread Title and inserting [SOLVED] at the beginning of it............

I've been trying to close this thread. I do not have the ability to do this in thread tools or in go advanced.