Hello, I am trying to shorten a part of my raw_field which is way too long : Host_Application="..." to only keep like 50 characters. And I noticed that NXlog is using PCRE syntax for finding a string in a field, but not for the substitution where it uses classic regex. I tried different things: Substitute with a regex the part I want but I can't, since it replaces everything I write in the regex. Find the exact string I want to replace with my PCRE rexgex, and then try to substitute it but I can't use the $1 field as the source string to modify. I would like to know if there is any way of doing what I want. Malauran