使用Regex查找某些文件类型

Question

Having issues trying to copy just jpg , png & JPG files starting with IMG_0000 from one directory to another. I have found the correct expression but I am struggling to make it work.

Below I have put the correct Regex as well as my code so far. The directory I am copying from is /root/memory and the target directory is /root/photoarch . Please note that inside /root/memory there are multiple sub-directories and multiple different file types.

Regex:

IMG_[0-9]{4}.[jpg,png,JPG]{3}

Code:

#!bin/bash
mkdir photoarch
find "/root/memory" -regex '.*IMG_[0-9]{4}.[jpg,png,JPG]{3}' -exec cp {} "/root/photoarch"\;

Answer 1

If you are trying to copy files named IMG_<4-digits>.<jpg|JPG|png> , then your regular expression is wrong, as well as its type (by default find uses Emacs RE, not POSIX ERE ).

Regarding the regular expression, you'll have to use alternation instead of character range. For example jpg|png will match either jpg or png . In contrast, [jpg,png]{3} will match any 3-character sequence of j or p or g or , or n , like jjj , j,p , and pnj . Also, you'll have to escape the dot (with \\. ), otherwise it will match any character.

To use POSIX ERE, set -regextype to posix-extended (to list all types accepted, run find -regextype help ).

For case-insensitive matching, you can use -iregex .

find /root/memory -regextype posix-extended -iregex '.*img_[0-9]{4}\.(jpg|png)' -exec cp {} /root/photoarch \;

(The parentheses around jpg|png are necessary because concatenation has higher priority than alternation.)