Linux Format - UK (2019-12)

http://www.techradar.com/pro/linux December 2019 LXF257 83

HOTPICKS

VISUALIZATION TOOL

NODE.JS MODULE REMOVER

Keep an eye on

your software and

middleware with

this robust CLI tool.

everal times in LXF we’ve moaned about

catchy yet useless apps like Hollywood

Technodrama. Dark-themed consoles with

running numbers, charts and other means of imitating

activity in a fictional mission-control board... At last, it’s

time to put that eye-candyish interface to good use,

with the help of Sampler.

This is a monitoring and alerting tool designed to

execute shell commands and keep you informed about

their progress or state. In some ways, Sampler is a

more basic CLI equivalent to Zabbix and other

monitoring solutions, so if you’re looking for a

lightweight tool that tracks dynamic processes,

Sampler is a good bet. The application offers a single

executable that accepts settings from a YAML

configuration file:

$ sampler --config /path/to/file.yml

The only thing left to do before you are ready to go is

create the contents of such a YAML file. Sampler

features a solid number of CLI visualisation modules for

displaying various charts and information boxes, this

Sampler

itself requires some skills in writing a config file. A good

starting point is to use the real-world recipes provided

by the project (follow the links in the readme file) and

see how Sampler works with SSH sessions, database

connections, Docker container statistics, Java JMX

monitoring and so on.

Don’t miss the impressive dashboard template

provided in the example.yml file. It’s a showcase for

many Sampler modules that work right out of the box.

For instance, there are ping response meters for

Google/Yahoo!/Bing, ASCII clocks, a CPU sparkline

chart, a weather applet and some other practical things.

By modifying the YAML file you can customise the

dashboard to your liking, add or remove commands or

their arguments in any way, rearrange blocks and so on.

It’s a splendid feature for many sysadmins.

Version: 1.0.3 Web: https://github.com/

sqshq/sampler

ore and more apps are based on JavaScript,

TypeScript and other *scripts these days.

That said, most of these apps have Node.js

under the bonnet, which means you need to use the

Node.js package manager (npm) in order to resolve

dependencies and run the application. Npm is a superb

tool that automates handling of the Node.js package

repository, which is claimed as the largest software

collection in the world with over 600,000 packages

(and counting).

The only concern is that the number of installed

Node.js packages on your local machine can grow huge

and eat too much disk space. This is especially

applicable to virtual machines or other setups with

relatively small partitions. Fortunately we have Npkill,

a maintenance tool for cleaning unneeded Node.js

packages and freeing up some disk space.

Npkill can be installed via npm:

$ npm i -g npkill

After that you will be able to run the npkill command

to use this app. Npkill is not a fully-fledged package

Npkill

manager – the only thing it can do is delete packages.

If run without extra arguments, Npkill rakes the entire

home directory searching for all node_modules

subdirectories. When this is done, you’ll see the whole

list of them along with the disk space they occupy.

Select a line with arrow keys and press Space to delete

the corresponding directory. That’s it!

No dependencies or anything else are taken into

account and therefore it is solely a user’s responsibility

not to break anything. To use Npkill wisely, try to

narrow down the scope by adding more arguments:

$ npkill -d ‘~/projects’ -gb --sort size

Here we’ve limited the search to a given directory

and sorted by file size.

Version: 0.6.0 Web: https://github.

com/voidcosmos/npkill

Get rid of that old

and dusty clutter

in ‘node_modules’

with ease.

M

S

DDDecmbr 202 eb198P 18apwok December 2019 LXF257 83

HOTPICKS

VISUALIZATIONTOOL

NODE.JSMODULEREMOVER

Keep an eye on

your software and

middleware with

this robust CLI tool.

everal times in LXF we’ve moaned about
catchy yet useless apps like Hollywood
Technodrama. Dark-themed consoles with
runningnumbers, charts and other means of imitating
activity in a fictional mission-control board... At last, it’s
time to put that eye-candyish interface to good use,
with the help of Sampler.
This is a monitoring and alerting tool designed to
execute shell commands and keep you informed about
their progress or state. In some ways, Sampler is a
more basic CLI equivalent to Zabbix and other
monitoring solutions, so if you’re looking for a
lightweight tool that tracks dynamic processes,
Sampler is a good bet. The application offers a single
executable that accepts settings from a YAML
configuration file:
$ sampler --config /path/to/file.yml
The only thing left to do before you are ready to go is
create the contents of such a YAML file. Sampler
features a solid number of CLI visualisation modules for
displaying various charts and information boxes, this

Sampler

itself requires some skills in writing a config file. A good

starting point is to use the real-world recipes provided

by the project (follow the links in the readme file) and

see how Sampler works with SSH sessions, database

connections, Docker container statistics, Java JMX

monitoring and so on.

Don’t miss the impressive dashboard template

provided in the example.yml file. It’s a showcase for

many Sampler modules that work right out of the box.

For instance, there are ping response meters for

Google/Yahoo!/Bing, ASCII clocks, a CPU sparkline

chart, a weather applet and some other practical things.

By modifying the YAML file you can customise the

dashboard to your liking, add or remove commands or

their arguments in any way, rearrange blocks and so on.

It’s a splendid feature for many sysadmins.

Version: 1.0.3 Web: https://github.com/

sqshq/sampler

oreandmoreappsarebasedonJavaScript,
TypeScriptandother*scriptsthesedays.
Thatsaid,mostoftheseappshaveNode.js
underthebonnet,whichmeansyouneedtousethe
Node.jspackagemanager(npm)inordertoresolve
dependenciesandruntheapplication.Npmisasuperb
toolthatautomateshandlingoftheNode.jspackage
repository,whichisclaimedasthelargestsoftware
collectionintheworldwithover600,000packages
(andcounting).
Theonlyconcernisthatthenumberofinstalled
Node.jspackagesonyourlocalmachinecangrowhuge
andeattoomuchdiskspace.Thisisespecially
applicabletovirtualmachinesorothersetupswith
relativelysmallpartitions.FortunatelywehaveNpkill,
amaintenancetoolforcleaningunneededNode.js
packagesandfreeingupsomediskspace.
Npkillcanbeinstalledvianpm:
$ npmi -gnpkill
Afterthatyouwillbeabletorunthe npkillcommand
tousethisapp.Npkillisnotafully-fledgedpackage

Npkill

manager – the only thing it can do is delete packages.

If run without extra arguments, Npkill rakes the entire

home directory searching for all node_modules

subdirectories. When this is done, you’ll see the whole

list of them along with the disk space they occupy.

Select a line with arrow keys and press Space to delete

the corresponding directory. That’s it!

No dependencies or anything else are taken into

account and therefore it is solely a user’s responsibility

not to break anything. To use Npkill wisely, try to

narrow down the scope by adding more arguments:

$ npkill -d ‘~/projects’ -gb --sort size

Here we’ve limited the search to a given directory

and sorted by file size.

Version: 0.6.0 Web: https://github.

com/voidcosmos/npkill

Get rid of that old

and dusty clutter

in ‘node_modules’

with ease.

M

S