You can use the command ls --color (or an alias) to show directories with colours for folders, files, links, etc. However, you may not realise these colours can be easily configured using bashrc and a configuration file.
My book Create Simple GUI Applications with Python & Qt5 has been updated! New chapters on multithreading and packaging your apps.
memcached is a general-purpose distributed memory caching system
originally developed by Danga Interactive for LiveJournal but now used
by many other sites. It is often used to speed up dynamic
database-driven websites by caching data and objects in RAM to reduce
the number of times an external data source (such as a database or API)
must be read. Here we describe the options available from the command
line to control a memcached instance via unix socket or IP:port.
A quick one-liner to recursively search files for a given text string.
Screen is a neat little program that allows you to use multiple virtual terminals in a single session on Unix/Linux and Mac. However, it does more than just that. It can also allow you to share your current session on a machine with another user - allowing you to collaboratively hack away at a problem in real time.
Bash command substitution performs a given command replacing the marker with the resulting standard output. It is particularly useful when you want to store the output of a command in a variable or as an alternative method of chaining multiple commands together.
A quick method to remove duplicates from text files - including for example CSV files - where multiple records have been added (perhaps automatically) at different times resulting in multiple copies of the same record scattered throughout the file. Here is a simple one-liner bash command to remove duplicates using sort.
System request (often abbreviated SysRq or Sys Req) is a key on keyboards for PCs that has no standard use. This key can be traced back to the operator interrupt key of the IBM System/370 mainframe computer. But under Linux there's a bunch of useful things available via this key.
Brace expansion is one of the most powerful bash tricks with the potential to save you considerable time. Here are some common use cases.
Find the currently running processes on your system that were not started by yourself. A great way to find out what is hogging your system on multiple-user setups or remote logins.
Often forgotten the
file command will give you a simple summary of a file's type and content.
Update your session to new settings in .bash_profile without logging out and back in again.
Find the pids of all instances/processes of a given program running on your system
Create your own bash pipes to send program output between shells, processes and users.
CDPATH is an environment variable which tells the
cd command where to look for the specified folder. By including the parent folders of commonly used locations you can access folders more easily - and without typing an entire path.
ifconfig.me is a web service that displays information about your connection, including IP address, hostname and User Agent string. Helpfully it provides a simplified interface that can be easily queried to get this information from the command line.
Re-run previously entered command as root user.
Bash history expansion allows you to quickly re-run previous commands using ! and the number of the command in your history.
Interactively search through your command line history with a simple keyboard shortcut.
GNU Screen is a command-line application that allows use of multiple virtual sessions within a single real terminal or remote session. Importantly, it allows for persistent running of command-line applications independent of the shell that initiated them program, meaning active applications can persist during disconnection.
When in a repository directory you can show the name of the currently checked out Git branch in the prompt, making it easier to track where you are (and where you're about to commit).
Show a warning in the Terminal's prompt when the current working directory is no longer where the shell expects it to be. (e.g. it was deleted or replaced by a new, different directory with the same name by some other app).