AppendixÂ A.Â Basic Linux for Non-Linux Users
In this appendix, we give a short introduction to the Linux filesystem for Windows (and Mac nonterminal) users. You will need this information because your application will be hosted on a Linux machine (Red Hat Enterprise Linux, in particular). One shortcut you should know right away is that the tilde character (~) is an alias for your home directory. The operating system will expand that symbol to the path to your home directory.
Listing Directory Contents
To list the contents of a folder, you can execute the
ls command. This will show the contents of the directory, but will not display any information about permissions or which items are directories. To view the permissions for items, use the command
ls -l. Use
ls -lh for human-readable file sizes, or
ls -lha to list all files, including hidden files. The output should look something like this:
[me@localhost tmp]$ ls -lha total 92K drwxrwxr-x. 3 me me 4.0K Jun 28 06:28 . drwx------. 58 me me 4.0K Jun 28 03:14 .. drwxrwxr-x. 2 me me 4.0K Jun 28 06:28 a_directory -rw-rw-r--. 1 me me 78K Jun 28 06:28 example.txt
Reading from left to right, the first 11 characters represent the file type and permissions. If the first character is a d, it means the line refers to a directory. The next three characters are the permissions for the user, the following three are the permissions for the group, and the next three are the permissions for the âworld.â Each character represents a differently capability: ...