Shell >> Redirections >> Capture

• Redirection meanings What ? Changing something.
• Instead of putting the output to the screen instead redirect to the file.
• ">" redirect and over write
• ">>" will always append.

#!/bin/bash
read -p "Enter ur name: " name
echo " Welcome to BOMBAY $name !!"

Also , you can choose which line needs to , go to the file.

#!/bin/bash
read -p "Enter ur name: " name 
echo " Welcome to BOMBAY $name !!" > log.txt
echo " Vanakam THozha " >> log.txt
echo " -- EOL -- "

/dev/null

• it will make it as NULL
• it will work only for the regular consoles.

1 --> console output ( By default it works only for standard console output ) eg., > or >>
2 --> Error

nohup

• script will run in background.
• the process will run behind us and it won't show in the console.
• it creates nohup.out
• & --> run it in the background.

#!/bin/bash
num=1
while [0]
do 
    echo "Number is $num"
    num = `expr $num + 1`
done

nohup file.sh 2>&1 &

Capturing

• back ticks var = ls | wc -l ``or
• $(command) var = $( ls | wc -l )

Both will return the value.

• One problem with backtick is " it wont support nested parameters ".

so use $()