If you need to start an x window after sudo ing as someone after doing ssh, you may run into permission problems, for example:   ssh -Y A@remote_machine su B xclock   it will fail. To grant such permission, as user A, type: xauth list then, copy the whole line.  Su to B, and type: […]

When in grub rescue, you only got insmod, ls, set, unset (I think). Thus, you must insmod the required modules in order to be able to do anything substantial. do: set root=<whatever> set prefix=<whatever>/boot/grub where <whatever> is like (md0) or (hd2,1). the /boot/grub is by default where modules are, so that insmod will work. If […]

subversion uses ssh. If ssh blocked from A to C, but A-> B and B->C is not blocked, setup tunneing:   1. on A: /etc/subversion/config in the [tunnel] section, add: ssh = $SVN_SSH ssh -o ControlMaster=no <machine B’s hostname> ssh -o ControlMaster=no   2. on B: /etc/ssh/ssh_config HostbasedAuthentication yes EnableSSHKeysign yes   3. on C […]

Introduction As an owner of a software and IT company, I love to solve technical problems. That’s why when recently sites I own and run, as well as my customers’ sites, were seemingly infected with malware (through no fault of mine or the company’s, more on this later), and having swiftly removed the said malware, […]

you su, then screen, and get:   “Cannot open your terminal ‘/dev/pts/3’ – please check.”   You instead need to run: screen < /dev/tty

Quick way to listen and serve data on a port: cat test.txt  | nc -l 8649

Installation Install hadoop: https://ccp.cloudera.com/display/CDHDOC/CDH3+Installation (optional) Links to installing hive/pig/hbase are on the bottom of the link in step 2. Configuration Hive:  by default it does not allow multiple users, because by default it uses a local derby metastore. So, if you wish to have multiple users connect to it, install mysql, and configure /etc/hive/conf/hive-site.xml.  See […]