I have log statement as follows as
1.20131220.server-0.log:2013-12-20 09:38:00,852 [fewfg424] SUCCESS: The FTP Server [et - FTP SERVER] uploaded file [Transaction_2_113237579.csv] of length 1989 bytes from userid [EBIDWNID].
2.20131209.dbg.log:2013-12-09 17:52:12,435 [58c858c8] SUCCESS: File successfully uploaded using SFTP. Filename was [nv_afis_nav_download12092013145008.csv]. File length was .
3.20131220.dbg.log:2013-12-20 09:36:35,575 [a468a] SUCCESS: File successfully uploaded using FTP. Filename [COR0083700_1.txt]. File length  bytes.
I want to write a regex common to these three statements to extract the filename and file length and display in table.Can anyone say how to write a common regex to extract filename and length.
I agree with Ayn, but perhaps something like the following will be useful.
'... | rex ".*?\[(?<filename>[\S]*?)\].*\slength[^0-9]*(?<length>[0-9]+)" | ...'
All the more reason to use separate regexes, but I think this will help you.
BTW, I like to use
http://www.regextester.com/index.html for testing regex strings.