Embedded developers working on kernels or bare-metal programs often go through several development cycles. Each time the developer modifies the code, the code has to be compiled, the ELF (Executable and Linkable Format)/kernel image has to be copied onto the SD card, and the card then has to be transferred from the PC to the development board and rebooted.

If you need a quick web server running and you don't want to mess with setting up apache or something similar, then Python can help. Python comes with a simple builtin HTTP server. With the help of this little HTTP server you can turn any directory in your system into your web server directory. The only thing you need to have installed is Python.

It's hard to write a bash script of much import without using a pipe or two. Named pipes, on the other hand, are much rarer.

If you work with the command line you've most likely used hexdump or od to dump binary files, but what do you do if you have a hex dump of something and you want to create the binary version of the data? Assuming your needs aren't too complex, the answer may be xxd. You can use xxd to dump binary files just like hexdump and od, but you can also use it to do the reverse: turn a hex dump back into binary.

I've recently written about using bash arrays and bash regular expressions, so here's a more useful example of using them to test IP addresses for validity.

Sure, it may be hard, but it is possible to give up graphical interfaces entirely—even in 2019. About three years back, I attempted to live entirely on the command line for 30 days—no graphical interface, no X Server, just a big-old terminal and me, for a month. I lasted all of ten days.

When working with regular expressions in a shell script the norm is to use grep or sed or some other external command/program. Since version 3 of bash (released in 2004) there is another option: bash's built-in regular expression comparison operator "=~".

For Linux users, the command line is a celebrated part of our entire experience. Unlike other popular operating systems, where the command line is a scary proposition for all but the most experienced veterans, in the Linux community, command-line use is encouraged.

If you don't want to step up to a full monitoring solution such as Nagios you can create your own scripts for monitoring the things that you want to monitor, such as disk space. The following script alerts you when your root partition is almost full:

iptables is the user-space tool for configuring firewall rules in the Linux kernel. It is actually a part of the larger netfilter framework. Perhaps because iptables is the most visible part of the netfilter framework, the framework is commonly referred to collectively as iptables. iptables has been the Linux firewall solution since the 2.4 kernel.