Etc Hosts Management Utility & Go Library

/etc/hosts Management

It is easy to open your /etc/hosts file in text editor and add or remove entries. However, if you make heavy use of /etc/hosts for software development or DevOps purposes, it can sometimes be difficult to automate and validate large numbers of host entries.

txeh was initially built as a golang library to support kubefwd, a Kubernetes port-forwarding utility utilizing /etc/hosts heavily, to associate custom hostnames with multiple local loopback IP addresses and remove these entries when it terminates.

A computer's /etc/hosts file is a powerful utility for developers and system administrators to create localized, custom DNS entries. This small go library and utility were developed to encapsulate the complexity of working with /etc/hosts directly by providing a simple interface for adding and removing entries in a /etc/hosts file.

txeh Utility

Install

MacOS homebrew users can brew install txn2/tap/txeh, otherwise see releases for packages and binaries for a number of distros and architectures including Windows, Linux and Arm based systems.

Install with go install

When installing with Go please use the latest stable Go release. At least go1.16 or greater is required.

To install use: go install github.com/txn2/txeh/txeh@master

If you are building from a local source clone, use go install ./txeh from the top-level directory of the clone.

go install will typically put the txeh binary inside the bin directory under go env GOPATH, see Go’s Compile and install packages and dependencies for more on this. You may need to add that directory to your $PATH if you encounter the error txeh: command not found after installation, you can find a guide for adding a directory to your PATH at https://gist.github.com/nex3/c395b2f8fd4b02068be37c961301caa7#file-path-md.

Compile and run from source

dependencies are vendored:

go run ./txeh/txeh.go

Use

The txeh CLI application allows command line or scripted access to /etc/hosts file modification.

Example CLI Usage:

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 \__/_/\_\___|_| |_| v1.5.0

Add, remove and re-associate hostname entries in your /etc/hosts file.
Read more including usage as a Go library at https://github.com/txn2/txeh

Usage:
  txeh [flags]
  txeh [command]

Available Commands:
  add         Add hostnames to /etc/hosts
  completion  Generate the autocompletion script for the specified shell
  help        Help about any command
  list        List hostnames or IP addresses
  remove      Remove a hostname or ip address
  show        Show hostnames in /etc/hosts
  version     Print the version number of txeh


Flags:
  -d, --dryrun         dry run, output to stdout (ignores quiet)
  -h, --help           help for txeh
  -q, --quiet          no output
  -r, --read string    (override) Path to read /etc/hosts file.
  -w, --write string   (override) Path to write /etc/hosts file.

# point the hostnames "test" and "test.two" to the local loopback
sudo txeh add 127.0.0.1 test test.two

# remove the hostname "test"
sudo txeh remove host test

# remove multiple hostnames
sudo txeh remove host test test2 test.two

# remove an IP address and all the hosts that point to it
sudo txeh remove ip 93.184.216.34

# remove multiple IP addresses
sudo txeh remove ip 93.184.216.34 127.1.27.1

# remove CIDR ranges
sudo txeh remove cidr 93.184.216.0/24 127.1.27.0/28

# quiet mode will suppress output
sudo txeh remove ip 93.184.216.34 -q

# dry run will print a rendered /etc/hosts with your changes without
# saving it.
sudo txeh remove ip 93.184.216.34 -d

# use quiet mode and dry-run to direct the rendered /etc/hosts file
# to another file
sudo txeh add 127.1.27.100 dev.example.com -q -d > hosts.test

# specify an alternate /etc/hosts file to read. writing will
# default to the specified read path.
txeh add 127.1.27.100 dev2.example.com -q -r ./hosts.test

# specify a separate read and write oath
txeh add 127.1.27.100 dev3.example.com -r ./hosts.test -w ./hosts.test2

txeh Go Library

Dependency:

go get github.com/txn2/txeh

Example Golang Implementation:

package main

import (
    "fmt"
    "strings"

    "github.com/txn2/txeh"
)

func main() {
    hosts, err := txeh.NewHostsDefault()
    if err != nil {
        panic(err)
    }

    hosts.AddHost("127.100.100.100", "test")
    hosts.AddHost("127.100.100.101", "logstash")
    hosts.AddHosts("127.100.100.102", []string{"a", "b", "c"})

    hosts.RemoveHosts([]string{"example", "example.machine", "example.machine.example.com"})
    hosts.RemoveHosts(strings.Fields("example2 example.machine2 example.machine.example.com2"))


    hosts.RemoveAddress("127.1.27.1")

    removeList := []string{
        "127.1.27.15",
        "127.1.27.14",
        "127.1.27.13",
    }

    hosts.RemoveAddresses(removeList)

    hfData := hosts.RenderHostsFile()

    // if you like to see what the outcome will
    // look like
    fmt.Println(hfData)

    hosts.Save()
    // or hosts.SaveAs("./test.hosts")
}

Build Release

Build test release:

goreleaser --skip-publish --clean --skip-validate

Build and release:

GITHUB_TOKEN=$GITHUB_TOKEN goreleaser --clean

License

Apache License 2.0