Screen is the best software used for full-screen window manager that multiplexes a physical terminal between several processes, typically interactive shells using only one SSH sesion or only one console.
Getting in
Escape key
All screen commands are prefixed by an escape key, by default C-a (that's Control-a, sometimes written ^a). To send a literal C-a to the programs in screen, use C-a a. This is useful when when working with screen within screen. For example C-a a n will move screen to a Read more...
Linux
Linux stuff
Servers that boot from SAN disks that require to upgrade the PowerPath version requires some aditional steps as you have to upgrade the software that handles the disk where the OS is running.
Below you can find the pdf oficial document from EMC that explain all the options to perform the upgrade.
Here I show a proved procedure to upgrade the software. To do so, Powerpath provides an script we can use to remove (or configure) the powerpath devices. We will use a mixture of both option, removing Read more...
For a clean output on the IP address for nslookup, create a file with the list of hosts be lookup and run:
# for i in `cat /tmp/list`; do echo -n $i": " ; getent hosts $i | awk '{ print $1 }'; done
To see the memory consuption in Solaris
# vmstat 1 2 |tail -1 | awk '{ print $5/1024, "MB"}'
To run a list of commands (i.e. over SSH)
for i in `cat file.host.list` ; do ssh -o ConnectTimeout=5 $i "$(<cmd.txt)" 1>> output.out; done
Where cmd.txt contains a list of commands separated Read more...
When connecting over ssh to a server with Putty, we can easily export the DISPLAY and run any X-Window application after enable the X11 in the PuTTY configuration. However, if you change to another account any X-Window application will fail as we have to share the MIT-MAGIC Cookies from the first user connected, here is how we can do it.
user1@server3$ echo $DISPLAY
localhost:10.0
user1@server3$ xauth list
server3/unix:10 MIT-MAGIC-COOKIE-1 6586998224e70480f72d195f55191dc4
server3/unix:11 Read more...
See the list of interfaces on which tcpdump can listen:
tcpdump -D
Listen on interface eth0:
tcpdump -i eth0
Listen on any available interface (cannot be done in promiscuous mode. Requires Linux kernel 2.2 or greater):
tcpdump -i any
Be verbose while capturing packets:
tcpdump -v
Be more verbose while capturing packets:
tcpdump -vv
Be very verbose while capturing packets:
tcpdump -vvv
Be verbose and print the data of each packet in both hex and ASCII, excluding the link level Read more...