0 and 7 both stand for Sunday, you can use the one you want, so writing 0-6 or 1-7 has the same result.

Also, as suggested by @Henrik, it is possible to replace numbers by shortened name of days, such as MON, THU, etc:

0 - Sun      Sunday
1 - Mon      Monday
2 - Tue      Tuesday
3 - Wed      Wednesday
4 - Thu      Thursday
5 - Fri      Friday
6 - Sat      Saturday
7 - Sun      Sunday

Graphically:

 ┌────────── minute (0 - 59)
 │ ┌──────── hour (0 - 23)
 │ │ ┌────── day of month (1 - 31)
 │ │ │ ┌──── month (1 - 12)
 │ │ │ │ ┌── day of week (0 - 6 => Sunday - Saturday, or
 │ │ │ │ │                1 - 7 => Monday - Sunday)
 ↓ ↓ ↓ ↓ ↓
 * * * * * command to be executed

Finally, if you want to specify day by day, you can separate days with commas, for example SUN,MON,THU will exectute the command only on sundays, mondays on thursdays.

https://stackoverflow.com/questions/18919151/crontab-day-of-the-week-syntax

HISTTIMEFORMAT="%d/%m/%y %T "  # for e.g. “29/02/99 23:59:59”
HISTTIMEFORMAT="%F %T "        # for e.g. “1999-02-29 23:59:59”

To make the change permanent for the current user run:

echo 'HISTTIMEFORMAT="%d/%m/%y %T "' >> ~/.bashrc  # or respectively
echo 'HISTTIMEFORMAT="%F %T "' >> ~/.bashrc
source ~/.bashrc

To test the effects run:

history

https://askubuntu.com/questions/391082/how-to-see-time-stamps-in-bash-history

You have */30 in the minutes specifier – that means every minute but with a step of 30 (in other words, every half hour). Since cron does not go down to sub-minute resolutions, you will need to find another way.

https://stackoverflow.com/questions/9619362/running-a-cron-every-30-seconds

Source: How to Integrate OnlyOffice with NextCloud on Ubuntu – LinuxBabe

System requirements

Installing Document Server

sudo apt-get install postgresql

sudo -i -u postgres psql -c "CREATE DATABASE onlyoffice;"
sudo -i -u postgres psql -c "CREATE USER onlyoffice WITH password 'onlyoffice';"
sudo -i -u postgres psql -c "GRANT ALL privileges ON DATABASE onlyoffice TO onlyoffice;"

sudo apt-get install redis-server

sudo apt-get install rabbitmq-server

sudo apt-get install nginx-extras

echo onlyoffice-documentserver onlyoffice/ds-port select <PORT_NUMBER> | sudo debconf-set-selections

sudo apt-key adv --keyserver hkp://keyserver.ubuntu.com:80 --recv-keys CB2DE8E5

sudo echo "deb https://download.onlyoffice.com/repo/debian squeeze main" | sudo tee /etc/apt/sources.list.d/onlyoffice.list

sudo apt-get update

sudo apt-get install onlyoffice-documentserver

Running Document Server using HTTPS

Additional information: more options for Document Server installation

Source: Installing Document Server for Linux on Debian, Ubuntu and derivatives – ONLYOFFICE

dn: olcDatabase={1}hdb,cn=config
changetype: modify
add: olcSuffix
olcSuffix: dc=test,dc=local
-
add: olcRootDN
olcRootDN: cn=admin,dc=test,dc=local
-
add: olcRootPW
olcRootPW: {SSHA}SGq737yNactRCyMY70TDTQs6V1wzMRD6
-
add: olcSyncRepl
olcSyncRepl: rid=004 provider=ldap://ldap1.test.local binddn="cn=admin,dc=test,dc=local" bindmethod=simple
  credentials=test searchbase="dc=test,dc=local" type=refreshOnly
  interval=00:00:00:10 retry="5 5 300 5" timeout=1
olcSyncRepl: rid=005 provider=ldap://ldap2.test.local binddn="cn=admin,dc=test,dc=local" bindmethod=simple
  credentials=test searchbase="dc=test,dc=local" type=refreshOnly
  interval=00:00:00:10 retry="5 5 300 5" timeout=1
olcSyncRepl: rid=006 provider=ldap://ldap3.test.local binddn="cn=admin,dc=test,dc=local" bindmethod=simple
  credentials=test searchbase="dc=test,dc=local" type=refreshOnly
  interval=00:00:00:10 retry="5 5 300 5" timeout=1
-
add: olcMirrorMode
olcMirrorMode: TRUE

Source: linuxlasse.net :: OpenLDAP N-Way MultiMaster Replication

https://community.letsencrypt.org/t/how-to-recreate-lets-encrypt-certificate-with-public-key-from-the-past/60096

We also want to password protect our phpLDAPadmin location. Even though phpLDAPadmin has password authentication, this will provide an extra level of protection.

The utility that we need is contained in an Apache utility package. Get it by typing:

sudo apt-get install apache2-utils

Now that you have the utility available, you can create a password file that will contain a username that you choose and the associated hashed password.

We will keep this in the /etc/apache2 directory. Create the file and specify the username you want to use by typing:

sudo htpasswd -c /etc/apache2/htpasswd demo_user

Now, we are ready to modify Apache to take advantage of our security upgrades.

Modify the phpLDAPadmin Apache Configuration

The first thing we will do is modify the alias that is set up to serve our phpLDAPadmin files.

Open the file with root privileges in your text editor:

sudo nano /etc/phpldapadmin/apache.conf

This is the place where we need to decide on the URL location where we want to access our interface. The default is /phpldapadmin, but we want to change this to cut down on random login attempts by bots and malicious parties.

For this guide, we’re going to use the location /superldap, but you should choose your own value.

We need to modify the line that specifies the Alias. This should be in an IfModule mod_alias.c block. When you are finished, it should look like this:

<IfModule mod_alias.c>
    Alias /superldap /usr/share/phpldapadmin/htdocs
</IfModule>

When you are finished, safe and close the file.

Configure the HTTP Virtual Host

Next, we need to modify our current Virtual Hosts file. Open it with root privileges in your editor:

sudo nano /etc/apache2/sites-enabled/000-default.conf

Inside, you’ll see a rather bare configuration file that looks like this:

<VirtualHost *:80>
    ServerAdmin webmaster@localhost
    DocumentRoot /var/www/html
    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

We want to add information about our domain name or IP address to define our server name and we want to set up our redirect to point all HTTP requests to the HTTPS interface. This will match the alias we configured in the last section.

The changes we discussed will end up looking like this. Modify the items in red with your own values:

<VirtualHost *:80>
    ServerAdmin webmaster@server_domain_or_IP
    DocumentRoot /var/www/html
    ServerName server_domain_or_IP
    Redirect permanent /superldap https://server_domain_or_IP/superldap
    ErrorLog ${APACHE_LOG_DIR}/error.log
    CustomLog ${APACHE_LOG_DIR}/access.log combined
</VirtualHost>

Save and close the file when you are finished.

The last thing we need to do is set up the location block that will implement our password protection for the entire phpLDAPadmin installation.

We do this by referencing the location where we are serving the phpLDAPadmin and setting up authentication using the file we generated. We will require anyone attempting to access this content to authenticate as a valid user:

<Location /superldap>
    AuthType Basic
    AuthName "Restricted Files"
    AuthUserFile /etc/apache2/htpasswd
    Require valid-user
</Location>

Save and close the file when you are finished.

Restart Apache to implement all of the changes that we have made:

sudo service apache2 restart

Source: How To Install and Configure OpenLDAP and phpLDAPadmin on an Ubuntu 14.04 Server | DigitalOcean