# USE1.1-I Command Line Interface
# Background

A shell provides advanced capabilities such as redirection of I/O, setup of pipelines and the management of jobs.

# Aim
  * To utilize convenient advanced features of the shell.

# Outcomes
  * Manage background jobs:
    * The commands fg, bg, jobs,
    * The meaning of the & character,
  * Describe the input and output channels:
    * 1, 2
  * Redirect input and output from/to files:
    * <<, <, >, >>, &
  * Design a pipeline for the processing of data using the pipe (|) symbol.
  * Assign and using shell variables and the export command.
  * Perform arithmetic operations on variables.
  * Replace the beginning or end of the text in the shell using the ${} notation.
  * Use widely available tools to understand and manage program execution:
    * top
    * ps (-a, -u, -x)
    * history
    * which
  * Use tools to search for relevant information and their arguments:
    * grep (-i, -v, -e)
    * cut (-b, -c, -f, -d)
    * sort (-r, -n, -k)
    * sed (for the basic search command and regular expressions)