Trim output to a terminal height and width.
The size of the terminal is fixed to default (20x80) when the file goes from stdin, for some reason term.GetSize returns an error, but when a file is specified as an argument it works as expected.
I need something that can proces large files more eficiently than awk version seeold/trim.sh and in one step will return line count too, so call exit() after this pseudo head output is unsuitable. Golang is the tool for that.
Below are tests:
$ wc zmaz.txt
88884 877907268 4389625224 zmaz.txt
$ stat zmaz.txt
File: zmaz.txt
Size: 4389625224 Blocks: 8573496 IO Block: 4096 regular file
$ ls -lh zmaz.txt
-rw-r--r-- 1 adrian adrian 4.1G Jun 28 11:57 zmaz.txt
# sh/awk version
$ time trim.sh < zmaz.txt
real 0m18.361s
user 0m19.352s
sys 0m5.381s
$ time ./trimgo < zmaz.txt
real 0m0.714s
user 0m0.235s
sys 0m0.486s
$ time ./trimgo zmaz.txt
real 0m0.714s
user 0m0.260s
sys 0m0.461s