linux – Page 3 – Eclipse Systems Knowledge Base

How do I launch a root shell from within Eterm?

It is sometimes useful to spawn a UNIX shell from within an Eterm session. Here is the procedure:

From within your active Eclipse session in Eterm
Press F2
Press T to launch the TCL shell
Type the following to launch a UNIX shell:
```
sh
```
Type the following to escalate the shell to superuser (root) mode:
```
su -
```
Enter the root user’s password when prompted
You are now at the root (#) prompt
To exit, type:
```
exit
exit
```
Press ESC at the TCL (;) prompt

Note: the user logged into Eclipse must have access to TCL, and you must know the root password.

For further reference, view a screencast of this procedure.

How do I fix a blank VNC session?

If you find yourself facing a blank VNC session, try restarting the VNC service. Log in to the server as root and run:

service vncserver restart

After the service has restarted, you should be able to return to a fully-functional VNC session.

This behavior typically results from a VNC user accidentally logging out of the GNOME desktop interface instead of simply disconnecting the VNC session.

How do I limit the size of CUPS log files?

To reduce the size of the CUPS logs:

Back up the existing configuration settings:

cp /etc/cups/cupsd.conf /etc/cups/cupsd.conf.`date +%Y%m%d.%H%M%S`

Open the /etc/cups/cupsd.conf configuration file in your favorite editor (i.e. vim, nano, Gnome editor, etc.).

Locate the MaxLogSize setting, and change it to a smaller value. For example, 100 MB:

MaxLogSize 100m

Restart the CUPS print service to apply the changes:

service cups restart

How do I manage core dumps on Linux?

To aid in troubleshooting, core dumps are sometimes enabled. A core dump file is the memory image of an executable program when it was terminated by the operating system due to various error behavior. Whenever a process is killed, a core.PID file will be created in the working directory.

If you are concerned about filesystem space, you may remove these files at any time.

If you would like to disable core dumps entirely, modify /etc/profile to contain the following line:

ulimit -S -c 0 > /dev/null 2>&1

If you wish to re-enable core dumps, change the same line to read:

ulimit -S -c unlimited > /dev/null 2>&1

If you want to check the status of core dumps, use the ulimit command:

[root@eclipse ~]# ulimit -a
core file size (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 1064960
max locked memory       (kbytes, -l) 32
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 10240
cpu time               (seconds, -t) unlimited
max user processes              (-u) 1064960
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited

How do I prevent my Seagate USB drive from powering down?

Seagate manufactures a number of low-cost USB hard drives that are popular with our customers. While these drives will certainly work for backup purposes, their unique power-saving features are known to cause issue with Linux systems. By default, the drives will power down after a period of inactivity to save power, and when they’re accessed again, they often come back as read-only filesystems. Unmounting and remounting the drive returns the drive to read-write mode, but there is a simple, long-term workaround to avoid this solution entirely.

To change the drive’s power saving setting, the drive must be disconnected from the Linux server and plugged into a Windows server or workstation with Seagate Dashboard installed.

Open Seagate Dashboard
Select the drive you wish to adjust by choosing it in the dropdown menu. If only one Seagate drive is available, it will be preselected.
Click Drive Settings in the Drives panel.
The Drive Settings window opens. Click Power Settings.
Select the “Never” interval from the dropdown menu.
Click Save to save the Drive Sleep Interval setting.
The Power Settings window confirms that the power setting for your drive has been changed.
Click Close to return to the Seagate Dashboard window.

For more information, please see Seagate’s KB entry on the subject.

The Eclipse Systems team continues to recommend RDX-based storage solutions, such as the Dell RD1000, for customers who wish to purchase certified and supported storage devices purpose-built for reliable backups.