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Bash Shell Programming HowTos

Tutorials, howtos and programming tips about GNU Bourne-Again SHell (BASH) for Apple OS X, Linux, *BSD and Unix like operating systems. ( rss feed )

How To Run Cronjob Script On The Last Day Of a Month

How to execute script on the last day of a month on Linux or Unix bash shell? How do I run a disk usage or custom reporting shell/perl/python script on the last day of a month on a Linux or Unix-like systems?
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How To: Temporarily Clear Bash Environment Variables on a Linux and Unix-like System

I‘m a bash shell user. I would like to temporarily clear bash shell environment variables. I do not want to delete or unset an exported environment variable. How do I run a program in a temporary environment in bash or ksh shell?
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How To Find the WiFi Password on Mac OS X

I‘ve MBP 13″ laptop. How can I find out the Wifi password on Mac OS X using command line and GUI options?
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Bash: Find out the exit codes of all piped commands

How do I get exit status of process that’s piped to another (for e.g. ‘netstat -tulpn | grep nginx‘) on a Linux or Unix-like system using a bash shell?
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Linux/Unix: How To Extract and Decompress a .bz2/.tbz2 File

I‘ve a file called foo.bz. How do I extract or decompress a .bz2 file on a Linux or Unix-like systems using command line options?
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How to run sudo command without a password on a Linux or Unix

I‘m a new Unix system user. How do I use sudo command without a password on a Linux or Unix-like systems?
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Ubuntu Linux: Edit and Open Files That Require Administrator Privileges

There are certain files in Ubuntu Linux (or Unix-like systems) that only root user access or edit. How can I edit and/or open files that requires admin (root) access on a Ubuntu Linux?
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Bash: Reissue And Repeat A Long Command Without Retyping It on a Linux, OS X & Unix

I‘m a new Ubuntu Linux user. In Linux, Apple OS X or Unix-like systems, how do I reissue or repeat a long command without retying it?
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FreeBSD Force DHCP Client (dhclient) to Renew IP Address To Get A New Lease

I have a Linux DD-WRT router DHCP server running on my network. How can I force my FreeBSD based dhcp client to get a new lease from this Linux based router? What is the command in FreeBSD equivalent to Windows’ “ipconfig /renew” command?
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How to Run and Execute Command When I Log Out Of Linux Session?

I‘m using CentOS 7 server. I need to run a command when I logout using ssh or bash shell. So in Linux and Unix-like systems, how can I run a command to execute when I log out my session?
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