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"!" in shell script

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# 1  
Old 06-24-2010
"!" in shell script
#!/bin/ksh
! radius.sh

can anybody tell us what does above shell script doing what does "!" means??

Thanks in advance
# 2  
Old 06-24-2010
In ksh, the ! is a logical negation operator. If the exit status of radius.sh is 0, then the exit status of the line becomes 1 and if the exit status of radius.sh is not equal to 0, the exit status of the line becomes 0.
# 3  
Old 06-24-2010
For example:
Code:
# ls > /dev/null
# echo $?
0
# ! ls > /dev/null
# echo $?
1

# 4  
Old 06-24-2010
Hi,
The line #!/bin/ksh is called a magic line. With the help of which no matter when ever u excute this script it will always run as a script executed in ksh shell...
So u dnt need to explicitly change shells and also u can be sure of all the commands as in ksh!!

Hope this helps...
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