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Command Line Cheatsheet

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How to login to the raspberry pi via terminal (SSH)

ssh [email protected]*** (*** = or IP-address from Pi or domain name)

Password = emonpi2016 (standard password if you didn’t change it)

Connecting via ssh

Safely shutdown or reboot a raspberry pi
after you logged in via SSH you can issue these commands

shutdown :

sudo shutdown -h now


sudo poweroff

reboot :

sudo shutdown -r now


sudo reboot

Factory Reset
Factory reset can be made by connecting via ssh then running:

sudo su

Warning - destroys all data!

Maintain crontab files

List cron for user Pi

crontab -l -u pi

List cron for root

sudo crontab -l		

Edit cron for user Pi *

crontab -e -u pi

Edit cron for root *

sudo crontab -e		

* for low-write emon devices, use rpi-rw to unlock filesystem and allow write access.

Determine emonSD image version

ls /boot | grep emonSD

To determine feed interval and start time of feed.

cd /home/pi/data/phpfina
od -i 1.meta


0000000       0       0       10     1435712370

10 is interval in seconds
1435712370 is start time in unix epoch

Submitted by chaveiro on Mon, 27/07/2015 - 12:30

Get status of all Services
Runs all init scripts, in alphabetical order, with the status command. The status is:
[ + ] for running services
[ - ] for stopped services and
[ ? ] for services without a ‘status’ command

sudo service --status-all


#emon Node-RED
including npm & node.js

Status or Restart of Node-RED Service
Use the below commands to get the status or restart Node-RED

sudo service nodered status
sudo service nodered restart

Version number of Node-RED

npm show node-red version
npm show node-red version -g

Node-RED items in syslog
Display Node-RED items saved in syslog

sudo cat /var/log/syslog | grep "Node-RED"

Output Node-RED items in syslog

sudo tail -f /var/log/syslog | grep "Node-RED"

Version of npm
npm is used for installing installing nodes for Node-RED

npm -v
sudo npm -v

List user installed Nodes with version info
run command from the Node-RED install directory

cd /home/pi/.node-red
npm list -g | grep emoncms
npm list | grep emoncms

Upgrade of NPM version 1.x to version 2.x *

sudo npm install -g [email protected]

* for low-write emon devices, use rpi-rw to unlock filesystem and allow write access.

Check for outdated Node-RED npm packages

npm outdated --prefix ~/.node-red


cd ~/.node-red
npm outdated

to check for outdated global npm packages:

npm outdated -g

Version of node.js

node -v
sudo node -v

Check if Redis is running

redis-cli PING

If running, the response should be “PONG”

Flush Redis

redis-cli flushall


#emon mySQL
Access mySQL database
for advanced users only (this leaves me out!)

mysql -u emoncms -p emonpiemoncmsmysql2016 emoncms

Show emoncms tables

mysql> show tables;

Display Feed info
Display ID number, feed id Name, Tag for feed, Datatype (realtime, daily, etc), Public (or private), Size of feed, Engine used for feed (phpfina or phptimeseries, etc.), and Process List for all Feeds

mysql> select * from feeds;



Selectively monitor log file in real time
Display new lines with a string (e.g., “NEW FRAME : OK 5”) in the emonhub.log file:

tail -f /var/log/emonhub/emonhub.log | grep "NEW FRAME : OK 5"

Selectively display log file
Display all lines with a string (e.g., “NEW FRAME : OK 5”) in the emonhub.log file:

cat /var/log/emonhub/emonhub.log | grep "NEW FRAME : OK 5"

Display all lines with two strings (e.g., “mqtt” or “mosquitto”) in the syslog file:

cat /var/log/syslog | grep -ie mqtt -e mosquitto


Thank you to @Paul, @bidouilleur, @Bill.Thomson, @Robert.Wall, @glyn.hudson, @pb66 for their help in creating this post.

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Resetting the emonCMS password

Can be done locally, or via SSH.
This assumes your emoncms admin account user name, and your database, are both named emoncms. If not, substitute your admin account username where you see the emoncms username, and your database name where you see the emoncms database name.

Create a new user from the emoncms login screen. For this example, we’ll give that user the name emontemp.

Take note of the password you gave the emontemp user.

Run Mysql as the MySQL root user:

mysql -u root -p (you’ll be prompted for the MySQL root user password)

Switch to your database. Substitute your database name if it’s not emoncms.
use emoncms

Copy emontemp’s password to the emoncms user account:

update users set password=(select * from (select password from users where username='emontemp') x) where username='emoncms'; (Substitue your username if it’s not emoncms.)

Copy emontemp’s password salt to the emoncms user account:

update users set salt=(select * from (select salt from users where username='emontemp') x) where username='emoncms';

Time saver tip: The two commands are the same save for the words password and salt. After you issue the first command, hit the up arrow key, change the two instances of password to salt, hit enter.
That’s it. You should be able to log on to your emoncms admin account with the password you gave emontemp.

Permanently authorising a connection to the emonPi

By creating a pair of Key Files - one on the emonPi and one on the machine you use to access it, you can remove the need to type a password each time you access the emonPi via SSH.

Note: this authorises the machine and whoever is using it to access the Pi, as distinct from a person who knows the password who is using the machine.

  1. Enable SSH on the emonPi / emonBase. For the emonPi only, use front panel LCD menu & pushbutton. Alternatively, for both (and the only way for the emonBase), add an empty file named “ssh” in the root partition.

  2. You must have SSH & SCP on the computer that’s being used.

  3. Generate a SSH key pair with “ssh-keygen” Don’t set a password - this authorises the MACHINE (vs the user] to update the emonPi / emonBase.

  4. This will generate the key files, in /home/[your user name]/.ssh
    The private key file, which you must keep secure, is id_rsa
    The public key file is

  5. Copy to the Pi with ssh-copy-id [remote id]
    e.g.remote-id = ‘[email protected]’,
    The SSH password “emonpi2016” is required this time only.

The SSH password will not be required again, unless you re-flash the SD card - in which case, repeat step 5 with the new SD card. You can use the same pair of key files with many emonPi’s, if you wish.

If you use puTTY,

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