The development of Unix began over 50 years ago. In contrast to commercial software, most of Unix's basic commands are still in use today. However, in the past couple decades, alternatives have been developed for a variety of reasons. For instance, restrictions such as lack of memory or color monitors or limits on file name lengths have long since disappeared, opening the way for more to be done with a command. Also, now that desktop environments are the norm, users demand more even at the command line. Sometimes, too, commands or some of their options have become obsolete or too numerous and too complex for their most common uses, resulting in the desire for simplification. At other times, developers want to try their hand at developing an improved version. Here are some of the new options for some common traditional commands.

tree or exa for ls

As one of the most commonly used commands for command-line navigation, ls is a popular choice for updating. If nothing else, the fact that many distributions routinely alias ls for ls --color highlights how much room there is for improvement. It's not surprising, then, that at least half a dozen replacements for ls exist, all of them routinely using color as well as other enhancements.

One popular replacement is tree. As the name suggests, tree displays results in a tree structure, making the results easier to read (Figure 1). With tree, you can specify the tree's depth, as well as the full path to each file. Conveniently, tree also includes five sorting orders. Also useful, tree allows for the customization of colors through environmental variables and shows the path to the original file for symlinks.

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