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Unix Tagged Q & A

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 ).

How to gzip and keep original file on Unix or Linux command line

I would like to compress a log file using gzip Unix command line utility, and I would also like to keep the original file. However, when I use the gzip my-app.log command, results in modifying my log file and renaming it my-app.log.gz. How do I force the gzip command to keep original file while maintaining the original file on Linux or Unix-like system?
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Unix / Linux: Remove duplicate lines from a text file using awk or perl

I have a text file with exact duplicates of lines. I need to remove all those duplicates lines and preserves the order too on Linux or Unix-like system. How do I delete duplicate lines from a text file?
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How to upgrade OpenSSH 7.0 to 7.2 on a OpenBSD Unix and Linux

OpenSSH version 7.2 has been released. How do I install or upgrade my existing OpenSSH version to 7.2 on a OpenBSD unix operating system?
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OS X install Amazon AWS command-line interface (CLI) tool

How do I setup and install the official Amazon AWS Command Line Interface (cli) on an Apple Mac OS X system?
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FreeBSD find the chmod numerical value for a file or directory

I need to find out the numerical value of a file on a FreeBSD system. For example, get 644 instead of -rw-r--r-- for the /etc/resolv.conf file. Is there is a way to get this value in my bash shell script?
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How to enable colorized output for the ls command in Mac OS X Terminal

I am new to Apple OS X. How do I enable colorized output for my ls command on Apple Mac OS X just like the ones that shown on my Ubuntu Linux server? How do I configure Mac OS X Terminal app to have color ls output?
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How to use curl command with proxy username and password on Linux or Unix

My sysadmin provided me the following proxy details:
       IP: 202.54.1.1
       Port: 3128
       Username: foo
       Password: bar

The settings worked perfectly with Google Chrome and Firefox browser. How do I use it with the curl command? How do I tell the curl command to use my proxy settings from Google Chrome browser?
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The OpenSSH project released an ssh client bug info that can leak private keys to malicious servers. A man-in-the-middle kind of attack identified and fixed in OpenSSH are dubbed CVE-2016-0777 and CVE-2016-0778. How do I fix OpenSSH’s client vulnerability on a Linux or Unix-like operating system?
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How to undefine and unset a bash environment variable on Linux or Unix

I have set the shell variable. I no longer need the variable. How do I undefine or unset a variable in bash on a Linux or Unix-like desktop system?
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FreeBSD find CPU (processor) temperature command

I‘m a new FreeBSD unix user. How do I get the temperature of an Intel or AMD processor (CPU) in FreeBSD using command line option?
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