To upload the cron job from a file to another user, combine it with -u option.

# crontab -u root /home/oracle/mycronjobs.txt

log a command to console and to 2 files separately stdout and stderr

# command > >(tee stdout.log) 2> >(tee stderr.log >&2)
_____

Real full backup copy of /etc folder
# rsync -a /etc /destination

If your repository is available on a server for e.g. 10.10.10.6, you need to point it to that server in your config file.

# cat /etc/yum.repos.d/rhel.repo
[base]
name=RHEL 5 $releasever - $basearch - Base
baseurl=http://10.10.10.6/yum/rhel/5/base/
enabled=1
gpgcheck=0

If the internet is not working from a server, you need to change one file.

cat /etc/resolove.conf

nameserver 8.8.8.8
nameserver 10.10.10.1
nameserver 10.10.10.6

/etc/init.d/network restart

The mail command will not work if the internet is down.

Download and Install redis from http://www.redis.io/download or use the following commands on the target server.

$ wget http://redis.googlecode.com/files/redis-2.2.8.tar.gz
$ tar xzf redis-2.2.8.tar.gz
$ cd redis-2.2.8
$ make

Start the redis server. To start the redis server please use the following command
$src/redis-server

configure the redis server ip in the Java properties file (cache.server) and ip (cache.port). The default port is 6379.

Important things to remember about Linux date:

* /etc/sysconfig/clock sets whether the hardware clock is stored as UTC or local time.
* Symlink /etc/localtime to /usr/share/zoneinfo/... to set your timezone.
* Run ``date MMDDhhmm'' to set the current system date/time.
* Type ``/sbin/hwclock --systohc [--utc]'' to set the hardware clock.

// copy the file to RAM - 30 times faster
cp -af /root/100mb.bin /dev/shm/

// increase it to 4GB
mount -o remount,size=4G /dev/shm

// new memory device
mkdir -p /var/www/www.mysite.com/ramdrive
mount -t tmpfs -o size=500M,mode=0744 tmpfs /var/www/www.mysite.com/ramdrive

// add it to /etc/fstab to make it permanent:
tmpfs /var/www/www.mysite.com/ramdrive tmpfs size=500M,mode=0777 0 0

660 mysql data dir
700 home directory
777 world writeable files
chmod +x asper.sh OR (chmod 754 asper.sh)

You can save the current file as a new file after making changes,
:w new_file.txt

If you want only 50 lines starting from line number 100, use...
:100,150w! new_file.txt

ps aux
When you run ps you will only get the first 40 or so characters displayed. In order to view the entire string, use ...
ps auxgww