Using Groovy as a command-line text file editor
The groovy
command, which we introduced in the Executing Groovy code from the command line recipe, can also be used as a stream editor or text file filter. In this recipe, we will cover the -i
, -n
, and -p
parameters that can be used to leverage file editing and processing functionality.
How to do it...
Assume that you have a file, data.txt
, which contains five lines with numbers from 1
to 5
:
- To multiply each number by 2, you can use the following command:
groovy -n -e "println line.toLong() * 2" data.txt
- We can even omit the
println
method call if we pass additional the-p
parameter to the command:groovy -n -p -e "line.toLong() * 2" data.txt
- In both cases, Groovy will print the following output:
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