sudo yum install screen2. start screen then type whatever process you want to keep running
screen # the command you want to keep running3. on keyboard issue ctrl-d 4. exist putty session 5. when you logon next time, you could restore the previous session by doing
screen -rPlease refer here for an alternative solution.
[sourcecode language="python"] your code here [/sourcecode]Supported languages are bash, python, java, JavaScript, perl etc.
sudo yum install tcl sudo yum install java-1.7.0-openjdk java-1.7.0-openjdk-devel sudo yum install sharutilsInstall Berkeley DB
wget http://download.oracle.com/berkeley-db/db-5.3.21.tar.gz
tar zvxf db-5.3.21.tar.gz
cd db-5.3.21/build_unix
# configure the program
../dist/configure --prefix=/opt --enable-compat185 --enable-dbm --disable-static --enable-cxx
make
# install
sudo make docdir=/usr/share/doc/db-5.3.21 install
sudo chown -v -R root:root /usr/bin/db_* /usr/include/db{,_185,_cxx}.h /usr/lib/libdb*.{so,la} /usr/share/doc/db-5.3.21
Questions: "libdb-5.3.so: cannot open shared object file: No such file or directory"
Answer:sudo /sbin/ldconfig
yum repolistIf you do not see EPEL in the output, then you have not enabled it yet. https://fedoraproject.org/wiki/EPEL 1. download the following package from fedoraproject.org
# The following link is for CentOS 5 wget http://dl.fedoraproject.org/pub/epel/5/x86_64/epel-release-5-4.noarch.rpm # check for and report potential conflicts rpm -ivh epel-release-5-4.noarch.rpm --testDuring test you might see the following NONKEY warning msg:
"warning: epel-release-5-4.noarch.rpm: Header V3 DSA signature: NOKEY, key ID 217521f6"wget http://fedoraproject.org/static/217521F6.txt mv 217521F6.txt /etc/pki/rpm-gpg/RPM-GPG-KEY-EPEL sudo rpm --import /etc/pki/rpm-gpg/RPM-GPG-KEY-EPELVerify that the key got installed
rpm -qa gpg*Now run the test command again you should not see NOKEY msg:
sudo rpm -ivh epel-release-5-4.noarch.rpm --test2. Enable the repository:
sudo rpm -ivh epel-release-5-4.noarch.rpm
/sbin/sysctl net.ipv4.ip_forwardif return
net.ipv4.ip_forward = 1 then it is enabled. if not edit /etc/sysctl.conf and set net.ipv4.ip_forward = 1. /sbin/sysctl -p /etc/sysctl.conf /sbin/service iptables restart3. Adding IP forwarding rules to IpTables
/sbin/iptables -I FORWARD 1 -m state --state ESTABLISHED,RELATED -j ACCEPT /sbin/iptables -I FORWARD 1 -p tcp --dport 80 -j ACCEPT /sbin/iptables -t nat -A PREROUTING -p tcp --dport 80 -j DNAT --to-destination 10.0.1.1:8080 /sbin/iptables -t nat -A POSTROUTING -j MASQUERADE /sbin/service iptables save /sbin/service iptables restartThe content of /etc/sysconfig/iptables files looks like:
# Generated by iptables-save v1.3.5 on Fri Mar 8 10:27:21 2013 *nat :PREROUTING ACCEPT [0:0] :POSTROUTING ACCEPT [0:0] :OUTPUT ACCEPT [0:0] -A PREROUTING -p tcp -m tcp --dport 80 -j DNAT --to-destination 10.0.1.1:8080 -A POSTROUTING -j MASQUERADE COMMIT # Completed on Fri Mar 8 10:27:21 2013 # Generated by iptables-save v1.3.5 on Fri Mar 8 10:27:21 2013 *filter :INPUT ACCEPT [0:0] :FORWARD ACCEPT [0:0] :OUTPUT ACCEPT [234:26336] :RH-Firewall-1-INPUT - [0:0] -A INPUT -j RH-Firewall-1-INPUT -A FORWARD -p tcp -m tcp --dport 80 -j ACCEPT -A FORWARD -m state --state RELATED,ESTABLISHED -j ACCEPT -A FORWARD -j RH-Firewall-1-INPUT -A RH-Firewall-1-INPUT -i lo -j ACCEPT -A RH-Firewall-1-INPUT -p icmp -m icmp --icmp-type any -j ACCEPT -A RH-Firewall-1-INPUT -p esp -j ACCEPT -A RH-Firewall-1-INPUT -p ah -j ACCEPT -A RH-Firewall-1-INPUT -p udp -m udp --dport 631 -j ACCEPT -A RH-Firewall-1-INPUT -p tcp -m tcp --dport 631 -j ACCEPT -A RH-Firewall-1-INPUT -m state --state RELATED,ESTABLISHED -j ACCEPT .... .... .... -A RH-Firewall-1-INPUT -j REJECT --reject-with icmp-host-prohibited COMMIT
ssh-keygenBy default, your public key file is located at
~/.ssh/id_rsa.pub and it can be shared with anyone. Your private key file is located at ~/.ssh/id_rsa and it must be kept secret. ssh-copy-id -i ~/.ssh/id_rsa.pub username@host1.example.net
2. Manual Installation
# copy the key to the remote host scp ~/.ssh/id_rsa.pub user@remotehost:id_rsa.pub # ssh into the remote host using your password ssh user@remotehost # append the public key cat id_rsa.pub >> ~/.ssh/authorized_keys rm id_rsa.pubON WINDOWS You can download puttygen.exe to generate private and public key pairs. Copy public keys generated to your remote host
~/.ssh/authorized_keys file and make sure they are in ONE LINE.
#List the current running cron jobs for currently logged in user: crontab -l #remove the jobs from crontab #It is a good practice to do so before modifying your script crontab -r #add cron jobs crontab /path/to/backup_script.cron
/etc/cron.allow file.#Add cron job for another user crontab -u username -e #list another user's cron job xrontab -u username -l
#run command_1 every 5 minutes (do not miss / in */5) */5 * * * * /path/to/command_1 #run command_2 every 5 hours (do not miss / in */5) 0 */5 * * * /path/to/command_2 # run command_3 1:30am everyday 30 1 * * * /path_to_command_3 # run command_4 1pm everyday 0 13 * * * /path_to_command_4
* * * * * env > /tmp/env.outputRestart crontab and wait for /tmp/env.output to be created, then remove the job again. Now compare the contents of
/tmp/env.output with the output of env running in your regular terminal.
The big differences is PATH environment variable.
To get around that, set your own PATH variable at the top of the script. E.g.
#!/bin/bash PATH=/opt/someApp/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin # rest of scron script follows