CLI mounting vs. GUI mounting

Question

why my program NOT printf ?

First asleep and then writes , but he should do it the other way round..

#include <stdio.h>
#include <stdlib.h>
#ifdef _WIN32
#include <Windows.h>
#else
#include <unistd.h>
#endif

void sleepMilliSecond(long milliSecondInput) {
#ifdef _WIN32
    Sleep(milliSecondInput); // v milliSecondach
#else
    usleep(pollingDelay * 1000); //microsekundy -> milisekundy
#endif
}



int main(int argc, char** argv) {  
    printf("start sleep");    
    sleepMilliSecond(1000);   //sleep 1s 
    printf("stop sleep");
    return (EXIT_SUCCESS);
}

Output of program is: sleep and then he write start sleep stop sleep, WHY?

EDIT: Working solution is:

printf("start sleep");    
fflush(stdout);
sleepMilliSecond(10000); 
printf("stop sleep");

Solution 1

Nautilus and other file managers that mount drives (i.e., the GUI) use the udisks command.

This provides a dynamic mount, where the mount point is created for the drive on-the-fly, and when the drive is unmounted, the mount point goes away.

See man 1 udisks for details on how to use this command (either manually, or called from a script/application). To learn more about how udisks works, see man 7 udisks.

To mount a device with udisks, you must specify a valid device name for the device. Specifying the device's volume name will not work. So, you can use udisks like this:

udisks --mount /dev/sdb1

When manually using udisks from the command-line, you might be best off to simply plug in a device, then run dmesg | tail shortly thereafter (see man dmesg and man tail) to discover the device name of the newly attached device.

This may not be the best way to write a script that mounts devices with udisks, however. I don't know exactly how you should do it, and it would be difficult to know since you haven't told us precisely what you want this script to do and when you want it to mount devices.

Solution 2

Since I do not want to automount on boot, fstab is out of the question (right?).

Nope. noauto keyword makes it skip mounting at boot time.

Is there an "easy" way to mount via CLI, just like it does on the GUI by clicking on an unmounted drive?

Easiest would be to add it to /etc/fstab with noauto and use ...

mount /dir

This will have mount probe for a mountpoint and if not found then for a device in /etc/fstab. /dir needs to exist though.

If either device or UUID are provided /etc/fstab is not probed. Like so ...

mount /dev/sda1 /media/directory

Or use udisks (I will let Eliah handle that >:-) )

---

mount generally is super user only.

Example options:

• rw,noauto,user mounts it as read+write but not at boot and you can do it as a user.

• You can also add in permissions for a user in /etc/fstab for files. You can use umask for that.

• umask=0444 : everyone read, no write, no execute.

• umask=0333 : everyone read, execute.

• umask=0338 : owner, group read and execute; others, nothing

Solution 3

In one of the comments, you said:

For whatever reason, I'm getting "Mount failed: Not Aouthorized" when running it via ssh

I use pmount instead of udisks. It works over ssh.

If I remember correctly, this is the syntax/etc I use with it - most of mine are hidden behind aliases at this point:

pmount /dev/sdb1 my_usb
ls /media/my_usb/
eject /media/my_usb

Solution 4

Use

udisks --mount /dev/sdb1

(replace /dev/sdb1 with the device you want to mount)

Solution 5

udisksctl

An update, FYI.

The command suggested in previous comment is not udisks anymore but udisksctl in recent linux distributions.

udisksctl mount -b /dev/sdc1

refereces

• https://manpages.ubuntu.com/manpages/bionic/man1/udisksctl.1.html
• https://wiki.archlinux.org/title/Udisks

View more solutions

Comments

[tilefrae]

For me no, because he write to console "START SLEEP" after sleeping interval :(

[SleuthEye]

printf is buffered. try fflush(stdout) after the first printf

[mch]

stdout is line buffered, you want to add a \n to print it immediately

[Paul Hankin]

pollingDelay isn't defined.

[Leushenko]

possible duplicate of Why does printf not flush after the call unless a newline is in the format string?

[NicApicella]

Thanks a lot -- udisks is exactly what I was looking for! For whatever reason, I'm getting "Mount failed: Not Aouthorized" when running it via ssh; if I'm not pushing my luck, pointers would be appreciated as to how to fix it. ^^

[Eliah Kagan]

@NicolaApicella How are you running it? You'll get a not authorized message if you try to run it from a remote session (including SSH) or from a crontab; by default non-root users can only mount volumes with udisks from local interactive logins. (They can still run a script from a local interactive login that uses udisks, though.)

[Eliah Kagan]

@Rinzwind Will a non-root user be able to mount the device?

[NicApicella]

@EliahKagan Yes, if you set the appropriate options in fstab (uid, user, ...).

[Eliah Kagan]

@NicolaApicella I'm hoping this answer might be expanded to include information about that. :)

[Rinzwind]

@NicApicella he likes to boss me around :=)

[tilefrae]

@The Paramagnetic Croissant not working fflush(stdout) help me.