Category: Software

Everything is a file in Linux

In UNIX and Linux everything is a File. Well almost.

The correct statement would be everything is a file descriptor or a process. The point to everything is a file is that common tools can be used. I/O access can be done using the same set of operations. In windows you have different reads for sockets, files and pipes with different.  With Unix/Linux treating everything as a simple file descriptor you have one read system call.  This removes the need for having multiple operations with specific uses doing the same thing.

As example of everything is a file we will take a look at a directory file.

I hope the high level overview in this video explained why to go deeper into this would get into kernel development and beyond what I do.

Linux ls command

In this video I go over the most important command in Linux which is the ls command. Ls is how to list directory content.

 

First we look at the ls man page.  then we go over some ls examples

Ls show hidden file (all)

ls -a

Ls long listing

ls -l

Ls recursive

ls -lR

Ls human readable file sizes

ls -hs

Sorting by size with ls

ls -AlhS

Shoring by size in reverse

ls -AlhSr

Sorting by modified time with ls

ls -Alt

Linux rev command

In this video I cover the rev or revers command in Linux. The rev command reverse lines characters. It comes with the util-linux package and can take input from a file or stranded out.

I think this command is little know because it doesn’t have many uses and there are other ways of doing it.