Shell
Advanced Math Calculation in Bash using GNU bc
Shell Tips
January 1, 2015 | COMMENTS

In this post, we will cover how to do advanced arithmetic and write your own functions with GNU bc.

If you are looking at doing basic arithmetic in a bash shell or using bc, you should take a look at my older post about Performing Math Calculation in Bash.

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disown a running shell process and reattach it to a new screen
Shell Tips
September 9, 2014 | COMMENTS

Stop worrying about your VPN connection dropping and your remote job to get kill. You can work on a remote server from your laptop or desktop in a safe and controlled way by detaching your screen session and reattaching later.

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sudo: sorry, you must have a tty to run sudo
Shell Tips
September 8, 2014 | COMMENTS

You just have configured your sudoers to execute some command without password from a ssh connection. Bummer, you just got an error:

sudo: sorry, you must have a tty to run sudo

No panic, there is an easy fix!

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redirecting a stdout to a file using sudo and tee
Shell Tips
September 8, 2014 | COMMENTS

When you attempt to modify a file without write permission on it, you will end-up with a permission denied error.

$ touch donottouch.txt && sudo chown root donottouch.txt
$ cat donottouch.txt
$ echo "change stuff" > donottouch.txt
-bash: donottouch.txt: Permission denied

Using sudo before echo won't help since the redirection will still apply within your shell environment. Here is few approaches to this problem.

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Download files from a Bash Shell
Shell Tips
July 9, 2011 | COMMENTS

Looking at downloading a file from a bash script but not sure where to start? Let me show you how to use wget, curl or download files with a shell script using Bash Redirections.

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