Need help understanding this script.


 
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# 1  
Old 10-25-2010
Need help understanding this script.

Can someone explain what is happening line by line in this script, particularly after the do statement. The script works, it renames all the files in my directory that has a date in the file name. But I would like to know more about it.

#!/bin/bash
newdate=12-10-1995
for file in *[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]*
do
mv $file ${file%[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9].*}$newdate${file#*[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]}
done
Harleyrci
# 2  
Old 10-25-2010
It tries to rename any file with 2-2-4 digit date in the name and replace that date with a new date, but it contains an error as the dot should not be there.
It use parameter expansion to accomplish this.
Code:
newdate=12-10-1995
for file in *[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]*
do
  mv "$file" "${file%[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]*}$newdate${file#*[0-9][0-9]-[0-9][0-9]-[0-9][0-9][0-9][0-9]}"
done

And it is better to put double quotes there.
# 3  
Old 10-25-2010
what does $file " "${file% -- do and $newdate${file#* -- whats this.
Harleyrci
# 4  
Old 10-25-2010
Quote:
Originally Posted by Harleyrci
what does $file " "${file% -- do and $newdate${file#* -- whats this.
It cuts of part of the string, see the link.
# 5  
Old 10-25-2010
Ok, thanks again.
Harleyrci
# 6  
Old 10-26-2010
Quote:
Originally Posted by Scrutinizer
It tries to rename ..., but it contains an error as the dot should not be there.
Unless the target filename has a real dot there.
This User Gave Thanks to KenJackson For This Post:
# 7  
Old 10-26-2010
Good point Smilie
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