CODEWITHSUNDEEP
linuxbashshellifs
user2999425
user2999425

Reputation: 125

IFS and moving through single positions in directory

I have two questions .

  1. I have found following code line in script : IFS=${IFS#??} I would like to understand what it is exactly doing ?

  2. When I am trying to perform something in every place from directory like eg.:

    $1 = home/user/bin/etc/something...

    so I need to change IFS to "/" and then proceed this in for loop like 

    while [ -e "$1" ]; do 
    for F in `$1`
        #do something
    done
shift
done

Is that the correct way ?

Upvotes: 0

Views: 74

Answers (1)

fedorqui
fedorqui

Reputation: 290515

${var#??} is a shell parameter expansion. It tries to match the beginning of $var with the pattern written after #. If it does, it returns the variable $var with that part removed. Since ? matches any character, this means that ${var#??} removes the first two chars from the var $var.

$ var="hello"
$ echo ${var#??}
llo

So with IFS=${IFS#??} you are resetting IFS to its value after removing its two first chars.

To loop through the words in a /-delimited string, you can store the splitted string into an array and then loop through it:

$ IFS="/" read -r -a myarray <<< "home/user/bin/etc/something"
$ for w in "${array[@]}"; do echo "-- $w"; done
-- home
-- user
-- bin
-- etc
-- something

Upvotes: 5

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