Introducing the Shell


Navigating Files and Directories


Figure 1

The file system is made up of a root directory that contains sub-directories titled bin, data, users, and tmp

Figure 2

Like other directories, home directories are sub-directories underneath "/Users" like "/Users/imhotep", "/Users/larry" or"/Users/nelle"

Figure 3

A directory tree below the Users directory where "/Users" contains the directories "backup" and "thing"; "/Users/backup" contains "original","pnas_final" and "pnas_sub"; "/Users/thing" contains "backup"; and"/Users/thing/backup" contains "2012-12-01", "2013-01-08" and"2013-01-27"

Figure 4

A directory tree below the Users directory where "/Users" contains the directories "backup" and "thing"; "/Users/backup" contains "original","pnas_final" and "pnas_sub"; "/Users/thing" contains "backup"; and"/Users/thing/backup" contains "2012-12-01", "2013-01-08" and"2013-01-27"

Figure 5

General syntax of a shell command

Working With Files and Directories


Figure 1

screenshot of nano text editor in action with the text It's not publish or perish any more, it's share and thrive

Shell Scripts


Pipes and Filters


Figure 1

Redirects and Pipes of different commands: "wc -l *.pdb" will direct theoutput to the shell. "wc -l *.pdb > lengths" will direct output to the file"lengths". "wc -l *.pdb | sort -n | head -n 1" will build a pipeline where theoutput of the "wc" command is the input to the "sort" command, the output ofthe "sort" command is the input to the "head" command and the output of the"head" command is directed to the shell