to lowercase(or uppercase) is not available with the gsub command about grok_exporter

[fstab]

Could you tell me what \\U\\0 is? Tried to look it up on https://ruby-doc.org/core-2.1.4/String.html but didn't find it.

[ohkik]

In the case of R, it seems that you can convert upper and lower case letters as follows:
toLowecase: gsub(pattern = '([[:upper:]])', perl = TRUE, replacement = '\L\1', n)
toUppercase: gsub(pattern = '([[:upper:]])', perl = TRUE, replacement = '\U\1', n)
https://stackoverflow.com/questions/30664444/gsub-error-turning-upper-to-lower-case-in-r

I thought I could use the same syntax in grok-exporter.

[fstab]

I implemented gsub as in the official Ruby documentation, so extensions like \U are currently not supported. It would be nice to have that as an additional feature though, so I'll leave this ticket open and will get back to it once the other features like supporting multiple log files are done.