Re: [LIH] 'if statement'

["Binand Raj S." <binand@xxxxxxxxxxxxxxxxxxxxx>]

Ashok forced the electrons to say:
> Could anyone tell me how to write an 'if' statement in bash shell
> programming

Four ways.

1. If you want to check a command is successful or not:

if ! grep -q '^root' /etc/passwd; then
	echo "Rootless system..."
fi

2. If you want to compare strings:

if [ "$TERM" = "dumb" ]; then
	echo "Set TERM to something nice..."
fi

3. Numerical checks:

if let "$a < 5"; then
	echo "a should be more than 5"
fi

This can also be written as:

if [ $a -lt 5 ]; then
	echo "a should be more than 5"
fi

4. File checks:

if [ ! -x /usr/bin/echo ]; then
	echo "Cannot execute /usr/bin/echo"
fi

This can also be written as:

if test ! -x /usr/bin/echo; then
	echo "Cannot execute /usr/bin/echo"
fi

Other associated keywords are 'else' and 'elif'.

I am posting this also to LIP. Followups there.

Binand

-- 
The prompt for all occasions:
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--------------- Binand Raj S. (binand@xxxxxxxxxxxxxxxxxxxxx)