Files

• cd - (change directory) used with no arguments takes us from wherever we might be to our home directory.
• pwd - (print working directory) tells in which directory we find ourselves for the moment.
• echo $HOME - Note that echo $HOME has exactly the same effect as pwd. Figure out what your home directory is. Now, What is $HOME?
• cat $>$ dict
  red: rojo
  yellow: amarillo
  black: negro
  white: blanco
  blue: azul
  green: verde
  $<$control-d$>$
  By $<$control-d$>$ we mean: hold the control key down; while it is down press "d". We have just used cat to create a short English-Spanish dictionary. This dictionary resides in the file dict.
• ls -al dict - lists the files in the current directory. For the moment there is only one, namely dict.
• cat dict - shows us what is in dict.
• wc dict - counts words (and more). In the case at hand it tells us that dict contains 6 lines, 12 words, and 78 characters ("letters").
• grep white dict - looks for the word white in the file dict and displays the lines in which this word appears. It gives us a way to search through files.
• sort dict - command does just what it says.
• sort dict $>$ dict2 - the use of the "into" symbol "$>$". In our example it had the effect of directing the output of the sort command from the screen to the file dict2.
  ls -al dict dict2 - be sure that dict2 was there.
  cat dict2 - be sure that the content is correct.
• rm dict2 - remove the file dict2.