Shell scripts are simple text files with commands to execute. The scripts are running by shell. All Bourne Shell scripts should begin with the sequence:



If you want to run a script you should give it suitable rights (command chmod).



Variable

---

If you want to assign a number or string of characters to the variable use symbol “=”.

variable=3
zmienna=”ala has cat”

If you want to assign a string of characters to the variable put quotation marks around the string.

variable=`date`

Each value on the command line is assigned to the special variables $1, $2, $3. $0 is the name of the script. $# is a count of values on the command line.



Print on screen

---

If you want to print message on screen use command echo. If you would like to print variable on screen add “$”symbol before variable.


This scripts print on screen „Date: --.--.—“



IF

---

If
Syntax:


In if condition we can compare two numbers :

number1 -gt number2 - number1 greates then number2
number1 -ge number2 - number1 greatest then or equal number2
number1 -eq number2 - number1 equal number2
number1 -le number2 - number1 little then or equal number2
number1 -lt number2 - number1 little then number2br />
Check or it is a file or a directory

-f filename – if filename is file
-d directoryname –if directoryname is directory
-e filename –if filename exist


Case

Case syntax:


Loop

---

For
Syntax:

for i in list
do
instrukcja
done

Example 1

for i in 123
do
echo $i
done

While
Syntax:

while [ condition ]
do
instrukcja
done