Unix Tutorials and HowTos

Question and answer for users of Unix-like operating systems. Topic includes – Unix commands, servers, security, networking, shell programming, troubleshooting and much more ( rss feed ).

I see lots of seasoned admins and cloud provider wrapper scripts use ssh client command as follows in shell:

ssh nixcraft@server1.cyberciti.biz --

What the double -- does here? Why it is used in this shell command and why not just use the following?

ssh nixcraft@server1.cyberciti.biz

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I am a small business and ecom site owner. I also run a WordPress based blog to connect with my customers. However, I get too much spam from certain IPs and net-blocks. How do I block access to certain url(s) such as example.com/blog/wp-comments-post.php for selected IP address and CIDRs? How do I allow everyone including IP address 1.2.3.4 to access my blog but block IP address 1.2.3.4 accessing only example.com/blog/wp-comments-post.php? How do I block POST requests for selected IPs/CIDR on nginx?

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How do I install Go language on Apple Mac OS X? How to setup GO lanuage on Mac OS X? How do I install Go language version 1.2+ on OS X?

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I manage MS-Windows server and recently started to play with OpenBSD server. How do I reload or restart the dhcpd server on OpenBSD using shell command line option?

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I am a new Nginx web server user. How do I redirect to a different domain using nginx (say example.org to example.com) permanently?

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I need to tunnel X Window securely over SSH bases session so that I run X program on my remote Linux/Unix server/workstation and get back display to my Apple Macbook pro laptop. I tried the ssh -X user@server1ssh -Y user@server2 command on both OS X Mountain Lion and Apple OS X Mavericks. But, I am unable to use the ssh command with X11

How do I fix this problem on OS X and enable X11 forwarding with ssh command? How do I install XQuartz (X11.app) server on Apple OS X Mountain Lion or Mavericks?

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To save the disk space on my Linux based nas (network storage server), I have compressed thousands of reports[0-1000].txt files using gunzip program. However, I need to cat .gz file (or open in vim text editor) for reference purposes. I have a log files stores on my nas server in compressed format using gzip command. How do I display compressed Apache log file without using cat command? How to display the contents of gzip text files in screen without unzipping?

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