Re: Bash: for…in-loop fails, what am I doing wrong?

[Johnny Rosenberg]

2013/1/10 Johnny Rosenberg <gurus.knugum at gmail.com>:
> Obviously I'm still a beginner at this. Here's a one-liner that
> demonstrates my problem:
>
> for File in "$(find ${PWD} -regextype posix-extended -regex
> '.*/P[A-Z0-9][0-9]{6}\.(jpg|JPG|jpeg)')"; do FileDate=$(date
> --reference="${File}" '+%Y%m'); done
>
>
> In a script, (easier to read…):
> for File in "$(find ${PWD} -regextype posix-extended -regex
> '.*/P[A-Z0-9][0-9]{6}\.(jpg|JPG|jpeg)')"

It's those quotes that cause my problems, isn't it?
But if I omit them, paths with spaces would go wrong, wouldn't they?
So what now…? :(

I could, of course, first do the find thing and redirect its output to
a file and then loop the file line by line… but I am not sure that
would help. I still have file paths with spaces in them… How to
separate a list with newlines and NOT with spaces? I guess that's the
tricky bit here…

More input still appreciated…


Johnny Rosenberg

Johnny Rosenberg


> do
>     FileDate=$(date --reference="${File}" '+%Y%m')
>     # More things to happen here, but this is only a test.
> done
>
> The regex works, and it finds files with names starting with P, then
> [A-Z0-9], then 6 numbers followed by .jpeg or .JPG or .jpg. Example:
> PA123456.JPG
> It finds them, that's not the problem.
>
> So what's the problem?
> Here's a faked output (the original output is too long):
>
> ~$ for File in "$(find ${PWD} -regextype posix-extended -regex
> '.*/P[A-Z0-9][0-9]{6}\.(jpg|JPG|jpeg)')"; do FileDate=`date
> --reference="${File}" '+%Y%m'`; echo "${FileDate}"; done
> date: /some/path/P1010077.jpeg
> /some/other/path/P1010018.jpeg
> /another/path/P1010023.jpeg
> /yet/another/path/P0000729.jpeg: File or directory does not exist
>
> ~$
>
> Maybe I totally misunderstood the for loop thing, but it seems like
> the date command is performed once for all paths at once, which is not
> what I want. I thought of it as an ordinary for loop in C, for
> instance, executing the date line once for each path name.
>
> What am I missing here? I'm probably just stupid, so I hope for your patience…
>
> Of course I have checked that those files exists; they are found by
> the find command, so they MUST exist, right?
>
>
> Johnny Rosenberg