| Unix Command | What it does |
|---|---|
| pwd | - indicates the current working directory |
| cd /usr/local/chemistry | - changes from current directory to "/usr/local/chemistry" |
| cd | - changes to home directory |
| ls | - lists files in current directory |
| ls -lt | - lists files with time and size |
| ls -lt | head | - lists the most recently created files |
The Unix shell acts as an interface between the user and the Unix operating system. It consists of high-level (human understandable) commands that tell the Unix operating system what to do. This information in turn is transferred to the hardware (CPU) in terms of low-level (machine understandable) commands. The user brings up a "window", called a Unix shell into which high-level commands are typed.