In bash, you can run multiple commands in a single line of a script. You do so by separating them with a semi-colon (;). The great thing about this is that if you end up using a variable, you can pass it on to subsequent commands. Here, we’re going to string three commands together and then echo the output: a=1;b=2;c=$a+$b;echo $c because we told c to be $a + $b, the $a expands to 1 and the $b expands to 2, we throw them together and then echo out the contents of c$ which appears as follows: 1+2 Now, we could have this thing do math as well, by wrapping…
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Linux Bash Commands
Popped in a list of Linux bash commands here: https://krypted.com//commands/linux-bash-commands/
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The 12 Days Of Krypted
Merry Christmas ya’ll! On the first day of Christmas my true love gave to me one 32 gig iPad On the second day of Christmas my true love gave to me two bash one-liners On the third day of Christmas my true love gave to me three Red Hat servers On the fourth day of Christmas my true love gave to me four email blasts On the fifth day of Christmas my true love gave to me five retweets On the sixth day of Christmas my true love gave to me six regular expressions On the seventh day of Christmas my true love gave to me seven lines of perl…
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Simple Preflight and Sanity Checking in Scripts
I was recently building some preflight scripts and was looking to record some information about a machine live, before proceeding with a script. I found the cheapest way to determine information about architectures and chipsets when scripting preflight scripts for OS X to be the arch and machine commands respectively. For example, to verify the architecture is i386, use the arch command with no options: /usr/bin/arch Which simply outputs “i386”: i386 To check the machine type, simply use the machine command: /usr/bin/machine Which outputs as follows: x86_64h
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Scripted Country Geolocations Using OS X’s Built-In ip2cc
Recently I was working on a project where we were isolating IP addresses by country. In the process, I found an easy little tool built right into OS X called ip2cc. Using ip2cc, you can lookup what country an IP is in. To do so, simply run ip2cc followed by a name or ip address. For example, to lookup apple.com you might run: ip2cc apple.com Or to lookup Much Music, you might run: ip2cc muchmusic.ca The output would be: IP::Country modules (v2.28) Copyright (c) 2002-13 Nigel Wetters Gourlay Database updated Wed May 15 15:29:48 2013 Name: muchmusic.com Address: 199.85.71.88 Country: CA (Canada) You can just get the country line: ip2cc…
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5 Ways To Manage Background Jobs In A Shell Environment
When running commands that are going to take awhile, I frequently start them with the nohup command, disown the command from the current session or queue them for later execution. The reason is that if I’m running them from a Terminal or SSH session and the session is broken I want to make sure they complete. To schedule a job for later execution, use at. For example, if I want to perform a simple command, I can schedule it in a minute by running it as an echo piped to at: echo "goldengirlsfix.sh" | at now + 2 minutes Note, if using 1 minute, you’ll need that to be singular.…
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Scripting Azure On A Mac
Microsoft Azure is Microsoft’s cloud services. Azure can host virtual machines and act as a location to store files. However, Azure can do much more as well, providing an Active Directory instance, provide SQL database access, work with hosted Visual Studio, host web sites or provide BizTalk services. All of these can be managed at https://manage.windowsazure.com. You can also manage Windows Azure from the command line on Linux, Windows or Mac. To download command line tools, visit http://www.windowsazure.com/en-us/downloads/#cmd-line-tools. Once downloaded, run the package installer. When the package is finished installing, visit /usr/local/bin where you’ll find the azure binary. Once installed, you’ll need to configure your account from the windowsazure.com site to…
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Units
Go figure, there’s a command that can convert some units to other units. The units command is able to take a number of one type of units and then convert them to another. For example, to convert a mile to feet: units "1 mile" feet Or to convert 2 hours to seconds: units "2 hours" seconds For a full listing of the formats supported, check out /usr/share/misc/units.lib.
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Leveraging The Useful Yet Revisionist Bash History
Not, this article is not about 1984. Nor do I believe there is anything but a revisionist history. Instead, this article is about the history command in OS X (and *nix). The history command is a funny beast. Viewing the manual page for history in OS X nets you a whole lotta’ nothin’ because it’s just going to show you the standard BSD General Commands Manual. But there’s a lot more there than most people use. Let’s take the simplest invocation of the history command. Simply run the command with no options and you’ll get a list of your previously run bash commands: history This would output something that looks…
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Grab The Currently Logged In User On OS X
You can ls /dev/console to see the currently logged in user of a machine. To do so: /bin/ls -l /dev/console You can also just grab the username, as follows /bin/ls -l /dev/console | /usr/bin/awk '{ print $3 }'