Xarrgs

A toy implementation of Xargs written in Golang. It's purpose was for me to practice some Go. Only a tiny subset of Xargs features are implemented.

Installation

go get github.com/amenasse/xarrgs

Usage

$ xarrgs -h

Usage of xarrgs:
  -max-chars int
    	Use at most max-chars per command line (default 2048)
  -max-procs int
    	Maximum number of processes to use (default 1)
  -null
    	items are seperated by a null not whitespace

Examples

# Perform work over 4 processes
$ cat input.txt | xarrgs  --max-procs 4 work

# Use at most max chars per command line
$ echo "An old silent pond..." | xarrgs --max-chars 10 echo
An old
silent
pond...


# Handle null terminated input
$ find . -type d -print0 | ./xarrgs -null du -s

Lessons Learnt

1. A slice references an underlying array.

   when passing a slice to a function or channel the same underlying array is still referenced by the receiver.

   From https://blog.golang.org/go-slices-usage-and-internals:

   "A slice is a descriptor of an array segment. It consists of a pointer to the array, the length of the segment, and its capacity (the maximum length of the segment)."

2. GNU Xargs and quotes

   GNU Xargs treats quotes specially by default. They are removed from the output. Quotes must be matched. Quoted text is seen as a single argument.