The fields subset of commands on Splunk is used to add, extract, and modify fields and field values. These commands help users enrich the data, do mathematical and string operations on the fields, and derive insight from the data.
eval command of Splunk is very useful and powerful. It can be used to evaluate Boolean, mathematical, or string expressions. It can also be used to create custom (new) fields using existing fields or arbitrary expressions. This command can be used to create new fields, which is the result of some calculations, or use conditional operators such as
match, and so on to apply some expression and evaluate the result.
eval command can also be used to coalesce fields from different sources ...