grep-go

README

Grep like CLI in go

Problem statement

Write a command line program that implements Unix command grep like functionality.

Features required and status

• Ability to search for a string in a file. Feel free to assume case-sensitive and exact word matches if required for simplicity’s sake.

$ ./mygrep "search_string" filename.txt
I found the search_string in the file.

• Ability to search for a string from standard input

$ ./mygrep foo
bar
barbazfoo
Foobar
food
^D

output -

barbazfoo
food

• Ability to write output to a file instead of a standard out.

$ ./mygrep lorem loreipsum.txt -o out.txt

should create an out.txt file with the output from mygrep. for example,

$ cat out.txt
lorem ipsum
a dummy text usually contains lorem ipsum

• Ability to search for a string recursively in any of the files in a given directory. When searching in multiple files, the output should indicate the file name and all the output from one file should be grouped together in the final output. (in other words, output from two files shouldn't be interleaved in the final output being printed)

$ ./mygrep "test" tests
tests/test1.txt:this is a test file
tests/test1.txt:one can test a program by running test cases
tests/inner/test2.txt:this file contains a test line

• Package test

Instruction to install and use

Important: It seems like you need to have go version >= 1.16. With github action build is failing on go version 1.15 because of io/fs package. I will fix this later.

$ go build -o grep
$ ./grep search_string input_file -o output_file

Benchmarks

goos: linux
goarch: amd64
pkg: github.com/itzmanish/grep-go/cmd
cpu: Intel(R) Core(TM) i5-5300U CPU @ 2.30GHz
BenchmarkRunSingleFile-4           	   14859	     72704 ns/op	   10295 B/op	      38 allocs/op
BenchmarkRunSingleFileParallel-4   	   19086	     74755 ns/op	    9867 B/op	      38 allocs/op
BenchmarkRunFolder-4               	   10000	    150037 ns/op	   36793 B/op	      94 allocs/op
BenchmarkRunFolderParallel-4       	   10000	    149637 ns/op	   37352 B/op	      95 allocs/op

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NOTE

This cli have all the features above mentioned. If input_file not provide cli gets input from Standard input.

If output_file not provided output will be on Standard Output.

No external dependencies.

Only standard library used.

Home Assessment task by One2N Consulting Private Limited

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