Explain: {,} in cp or mv Bash Shell Commands

I often see commands as follows posted on blog or forums

cp /etc/httpd/httpd.{,.bakup}

OR

mv resume{z,}.doc

What is the purpose of {,} in Linux and Unix shell commands?

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Ubuntu Copy File Command

I 'm a new Ubuntu Linux user. This seems like a newbie question, but I can not seem to find examples to copy files on Ubuntu. How do I copy file to another directory on Ubuntu Linux using command line terminal application? How can I copy files via terminal on Ubuntu Linux desktop?

You need to use cp command to copy file to another directory or external usb disk. The command line syntax is as follows to copy files via terminal:

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Linux: Log Suspicious Martian Packets / Un-routable Source Addresses

I run a web-server and I would like to log packets with un-routable source addresses on Linux operating system. How can I log spoofed packets on Debian / Ubuntu / CentOS / RHEL / Linux based server? How can I log a Martian packet (packet from Mars) on Linux operating systems?

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Increase NFS Client Mount Point Security For a Web-Server noexec, nosuid, nodev Options

I am using NFS server version 4.x on a CentOS/RHEL based system. I'm mounting my shared /var/www/ directory on five Apache based nodes using the following syntax:

mount -t nfs4 -o rw,intr,hard,proto=tcp rocknas02:/httproot/www /var/www/

I noticed that due to bug in my app user can sometime upload executable or other device files to get out of chrooted Apache server. How can I prevent such security issues on a CentOS or RHEL based NFS client and sever setup?

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HowTo: Prevent Yum From Upgrading The Kernel On a CentOS / Red Hat Enterprise Linux

I am a new RHEL / Centos Linux server admin. I would like yum to update all packages except the Linux Kernel. How can I prevent yum command from updating kernel on a CentOS/RHEL/Fedora Linux based systems?

You can prevent yum command from updating the Kernel permanently by following the simple steps.

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Unix / Linux: Check New Files In File System /var/www/uploads/

Recently, I switched from MS-Windows based web-server to CentOS Linux based Apache web-server. All user uploaded files are stored in /var/www/uploads/ directory. Is there command that can give me a list of files that have been added to the filesystem at /var/www/uploads/ in last 7 days on Linux/Unix-like oses?

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Linux / Unix: Check Last Time User Logged In On The System

am a new Unix system admin. How do I find ouw who has recently use the Linux or Unix-like server? Which terminals they used, and when they logged in and out of the my server?

You need to use last command. This command displays last logins of users and ttys.

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