B4J Question Set Date and Time from code

micro · Jan 3, 2016

Hi to all
it's possible with B4j change The System Date and Time directly from code?
Thanks

Erel · Jan 4, 2016

Settings the date and time on Windows requires administrator privileges. If the process is started as an administrator then you can use jShell to set the date and time. See the second answer here: http://stackoverflow.com/questions/6203857/how-can-i-set-the-system-time-in-java

micro · Jan 4, 2016

Thanks for your answer, my question is for raspberry (linux system).
Best regards

DonManfred · Jan 6, 2016

micro said:
my question is for raspberry (linux system)

The solution will be the same; using JShell.

But i dont know the command you need to use on a Raspberry PI to set the time.

micro · Jan 6, 2016

DonManfred said:
But i dont know the command you need to use on a Raspberry PI to set the time.

infact is this the problem.
Thanks

DonManfred · Jan 6, 2016

micro said:
infact is this the problem

Yes? 10 Seconds googling and i found this
https://www.raspberrypi.org/forums/viewtopic.php?f=63&t=13313

In fact it i the FIRST result from this google search.

So call

sudo date -s "Thu Aug 9 21:31:26 UTC 2012"

with jshell i guess

micro · Jan 6, 2016

Very well, thanks.

micro · Jan 30, 2016

Hi to all
is correct formatting this command?

B4X:

Dim js As  Shell
js.Initialize("", "date", Array As String("-s", d))
js.Run(-1)

Where d = "Sat Jan 30 08:10:12 CET 2016"

If i send the command from putty it's work but with b4j not (On Raspberry in debug mode, other commands work).
Thanks

billzhan · Jan 30, 2016

I guess the sudo is needed here. The default user 'pi' doesn't have the priv to change system settings.

B4X:

'try
js.Initialize("", "sudo", ArrayAsString("date","-s", d))

'or you should start the jar ( your complied jar/ b4j_bridge ) with sudo

micro · Jan 30, 2016

billzhan said:
'try
js.Initialize("", "sudo", ArrayAsString("date","-s", d))

Not work

billzhan said:
'or you should start the jar ( your complied jar/ b4j_bridge ) with sudo

so I do

billzhan · Jan 31, 2016

micro said:
so I do

I forgot to mention that sudo has a timeout limit (5 minutes or so) and you have to provide password.

It should work if you are running *.jar with root account.

micro · Jan 31, 2016

billzhan said:
It should work if you are running *.jar with root account.

yes, I start the jar wit root account but strangely does not work.
I tried also with ssh library (for B4A)

B4X:

Sub SetSSH
    Try
        ssh.Initialize("ssh", "127.0.0.1", 22)
        ssh.DebugOutput = False
        ssh.authenticateWithPassword("pi", "raspberry")
        ssh.execCommand("sudo date -s " & d, 10)
    Catch As Exception
        Log(LastException.Message)
    End Try
End Sub

but the problem is the same.

It's possible set the date from file with -f option?

billzhan · Jan 31, 2016

You need to enable the super user "root” ( and change PermitRootLogin if you use ssh ). sudo may not work
ssh.authenticateWithPassword("root", "rootpasswd")

http://www.raspberry-projects.com/pi/command-line/root-user-privileges

Enabling The Root Account
By default the root account is disabled, but you can enable it by using this command and giving it a password

sudo passwd root
Now you can log into your pi as the root user. Whilst this opens up security concerns its sometimes very useful, for instance when developing with netbeans and remotely running applicaiotn that access the IO pins.

If it doesn't work check the ssh config

sudo nano /etc/ssh/sshd_config

Search for PermitRootLogin and change it to yes

You can undo logging in as root again using this command

sudo passwd -l root

micro · Jan 31, 2016

Thanks for all
but why with putty and simply with "sudo date -s xxxxxxxxxxxxxxx" it's work?

Erel · Jan 31, 2016

Are you using B4J-Bridge to start the program?

Start B4J-Bridge with sudo and the sub-processes will also have root access.

micro · Jan 31, 2016

Erel said:
Are you using B4J-Bridge to start the program?

Yes (with sudo)

Erel · Jan 31, 2016

Are you checking the outputs (StdOut and StdErr)?

micro · Jan 31, 2016

Erel said:
Are you checking the outputs (StdOut and StdErr)?

Yes ther'isnt Errors

Erel · Jan 31, 2016

How can you check the outputs if the event name was set to ""?

Are you handling the ProcessCompleted event?

micro · Jan 31, 2016

Sudo java -jar b4j-bridge.jar > sdtout.txt 2> sdterr.txt

Or do I need another set?

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