What is the difference between the dir and ls commands?

Answer 1

From the user's point of view, there is very little difference between dir on windows or dos and ls on Unix. Anyone who has looked at the will see that ls has a lot more command line switches than dir - most of the alphabet, in fact. (This lead a couple of juvenile colleagues to see what rude words they could make with them and still get usable output!)

At a deeper level there are some differences:

dir is built in to the operating system and ls is an external program, so that dir should always work, but ls will only work if it is installed and in the path. (Which, of course, it will be unless something has gone wrong!)

Whilst file types or extensions (such as *.doc, *.txt) are used in Unix to assist humans to differentiate files, Unix has no built in concept of these whereas dos/Windows expects them. So the dos command:

dir *.* will show all files in a directory, but in Unix

ls *.* will only show files with a dot in the name, ls * is more likely to give the result expected.

Also, Unix style "[" and "]" can be used to define a group, so that: ls prog.[oc] will match prog.c and prog.o (but not prog.oc)

From the above, it can be seen that both recognise wildcards (* and ?). However, Unix treats them differently. In dos, the wildcard is presented unchanged to the command (DIR in this case) and the command has to understand and interpret it. In Unix, the operating system processes the wild card and presents the results to the command. From the user's perspective, there is normally no difference but it can have subtle effects and is worth being aware of.

Answer 2

see the options in man dir and man ls