Shell Cheat Sheet (DRAFT) by Torvak

-------------WHILE LOOP---------
a=0
while [ $a -lt 10 ]
do
   echo $a
   a=
expr $a + 1
done
-------------FOR LOOP(1)------------
for var in 0 1 2 3 4 5 6 7 8 9
do
   echo $var
done
------------FOR LOOP(2)-------------
for FILE in $HOME/.bash*
do
   echo $FILE
done
-----------FOR LOOP(3)-------------
nbLigne=1
for i in $(ls) 
do 
	echo "$nbLigne -> $i"
	nbLigne=$((nbLigne+1))
done
----------FOR LOOP(4)--------------
for TOKEN in $*
do
   echo $TOKEN
done
----------UNTIL LOOP----------------
a=0
until [ ! $a -lt 10 ]
do
   echo $a
   a=
expr $a + 1
done
---------SELECT LOOP------------
select DRINK in tea cofee water juice appe all none
do
   case $DRINK in
      tea|cofee|water|all) 
         echo "Go to canteen"
         ;;
      juice|appe)
         echo "Available at home"
      ;;
      none) 
         break 
      ;;
      *) echo "ERROR: Invalid selection" 
      ;;
   esac
done
-------------SIMPLE BREAK--------------
a=0
while [ $a -lt 10 ]
do
   echo $a
   if [ $a -eq 5 ]
   then
      break
   fi
   a=
expr $a + 1
done
-----BREAK WITH ARGUMENT----
for var1 in 1 2 3
do
   for var2 in 0 5
   do
      if [ $var1 -eq 2 -a $var2 -eq 0 ]
      then
         break 2
      else
         echo "$var1 $var2"
      fi
   done
done
NOTE: a break command with the argument 2->break out of outer loop and ultimately from inner loop as well.
---------CONTINUE-----------
NUMS="1 2 3 4 5 6 7"

for NUM in $NUMS
do
   Q=
expr $NUM % 2
   if [ $Q -eq 0 ]
   then
      echo "Number is an even number!!"
      continue
   fi
   echo "Found odd number"
done

/------------IF_ELIF_FI------------/
#!/bin/sh

a=10
b=20

if [ $a == $b ]
then
   echo "a is equal to b"
elif [ $a -gt $b ]
then
   echo "a is greater than b"
elif [ $a -lt $b ]
then
   echo "a is less than b"
else
   echo "None of the condition met"
fi

RESULT: a is less than b

/-----SIMPLE CASE...ESAC EXAMPLE------/
FRUIT="kiwi"

case "$FRUIT" in
   "apple") echo "Apple pie is quite tasty." 
   ;;
   "banana") echo "I like banana nut bread." 
   ;;
   "kiwi") echo "New Zealand is famous for kiwi." 
   ;;
esac
RESULT: New Zealand is famous for kiwi.

/----COMPLEXE CASE_ESAC-----/
option="${1}" 
case ${option} in 
   -f) FILE="${2}" 
      echo "File name is $FILE"
      ;; 
   -d) DIR="${2}" 
      echo "Dir name is $DIR"
      ;; 
   *)  
      echo "
basename ${0}
:usage: [-f file] | [-d directory]" 
      exit 1 # Command to come out of the program with status 1
      ;; 
esac 

EXAMPLE RUN OF THE PROGRAME: 
$./test.sh
test.sh: usage: [ -f filename ] | [ -d directory ]
$ ./test.sh -f index.htm
$ vi test.sh
$ ./test.sh -f index.htm
File name is index.htm
$ ./test.sh -d unix
Dir name is unix