How to Increase Bash History Size
Some valuable or complex commands may not be able to keep in your mind constantly when you need them. In this moment, you can leverage… Read More »How to Increase Bash History Size
Linux
How to Resolve RTNETLINK answers: Invalid argument Error adding default gateway
RTNETLINK answers: Invalid argument When I restarted the newly configured network interface, it returned error rtnetlink answers: invalid argument like the following: [root@test ~]# service… Read More »How to Resolve RTNETLINK answers: Invalid argument Error adding default gateway
How to Add a Second IP Address to Current NIC
Let's see current setting of all interfaces.[root@test ~]# ifconfigeth0 Link encap:Ethernet HWaddr 00:0C:29:D8:AE:2D inet addr:10.0.0.152 Bcast:10.0.0.255 Mask:255.255.255.0 … Read More »How to Add a Second IP Address to Current NIC
How to Compare Contents of Two Directories
After you copied one directory to another like this:$ cp -rp /path/to/source/directory /path/to/target/or mirrored the source directory to the target one.$ rsync -av /path/to/source/directory/ /path/to/target/directory/You… Read More »How to Compare Contents of Two Directories
When Backspace Key is Not Working in Console
If your Backspace key is not working in the current console, you may try the following ways to work around it:Ctrl + BackspaceCtrl + HCtrl +… Read More »When Backspace Key is Not Working in Console
The Size Limit for Legacy Tar to Accomodate
A quote from wikipedia:Numeric values are encoded in octal numbers using ASCII digits, with leading zeroes. For historical reasons, a final NUL or space character… Read More »The Size Limit for Legacy Tar to Accomodate
How to Limit Network Access By Firewalld on Enterprise Linux 7
You may have noticed that the service ssh is also added in the public zone (/etc/firewalld/zones/public.xml) by default. This is necessary for initialization. But after… Read More »How to Limit Network Access By Firewalld on Enterprise Linux 7
How to Kill All Background Processes in One Command on Linux
For executing batch jobs invisibly, system administrators usually schedule jobs in crontab or execute them in the background. Of course you can use fg to… Read More »How to Kill All Background Processes in One Command on Linux
How to Authorize Users to Use Crontab
Check /etc/cron.deny first If there's no /etc/cron.allow in your system, please make sure the user (e.g. oracle) that we would like to authorize it here… Read More »How to Authorize Users to Use Crontab
How to Resolve Crontab Error crontab: installing new crontab "/tmp/crontab":1: bad command errors in crontab file, can't install.
crontab: installing new crontab When I tried to save and quit editing crontab, I met an error like this: [oracle@test ~]$ crontab -e crontab: installing… Read More »How to Resolve Crontab Error crontab: installing new crontab "/tmp/crontab":1: bad command errors in crontab file, can't install.