1  ls -l
    2  ls nogots
    3  ls -la > ls-la
    4  cat ls-la
    5  ls asdfasafsfd > afile
    6  cat afile
    7  ls dflkaslfdjalsfjsl > afile 2> anerrflie
    8  ls -l a*
    9  cat anerrflie
   10  y=17
   11  z=42
   12  s="a string
that spans more than
one line
until it sees a
double quote"
   13  echo $s $y $z
   14  echo $PS1
   15  PS1="whazzup? "
   16  echo $PS2
   17  PS1="Yes, master, what is thy command? "
   18  send money
   19  echo huh?
   20  PS1="eh? "
   21  PS1="yeah, whadda ya want? "
   22  PS1="\s-\v\$"
   23  PS1="\s-\v\$ "
   24  echo $HOME
   25  echo $PATH
   26  ls /bin
   27  ls /usr/bin
   28  echo $PATH
   29  gcc --version
   30  which gcc
   31  PATH=$PATH:.
   32  echo $PATH
   33  ls
   34  countdown one II 3
   35  printenv|more
   36  bash
   37  echo $X $Y $Z
   38  echo $x $y $z
   39  unset x
   40  unset y
   41  unxet z
   42  unset z
   43  Y=17
   44  Z=42
   45  echo $X $Y $Z
   46  X=$Y+$Z
   47  echo $X $Y $Z
   48  ((X=$Y+$Z))
   49  echo $X $Y $Z
   50  ((X=Y*Z))
   51  echo $X $Y $Z
   52  let X=Z=Y
   53  echo $X $Y $Z
   54  let X=Z+Y
   55  echo $X $Y $Z
   56  if [[ $X -gt $Y ]]; then   echo yes; else   echo no; fi
   57  if [[ $X -gt $Y ]]; then   echo yes; else   echo no; fi
   58  k=3
   59  echo $k
   60  echo $$k
   61  echo ${$k}
   62  echo ${${k}}
   63  x="*"
   64  echo $x
   65  echo x
   66  echo "$x"
   67  echo '$x'
   68  ls
   69  ls [a-f]*
   70  history > lec5.history