Bash Word splitting Usefulness of word splitting
Example
There are some cases where word splitting can be useful:
Filling up array:
arr=($(grep -o '[0-9]\+' file))
This will fill up
arrwith all numeric values found in file
Looping through space separated words:
words='foo bar baz'
for w in $words;do
echo "W: $w"
done
Output:
W: foo
W: bar
W: baz
Passing space separated parameters which don't contain white spaces:
packs='apache2 php php-mbstring php-mysql'
sudo apt-get install $packs
or
packs='
apache2
php
php-mbstring
php-mysql
'
sudo apt-get install $packs
This will install the packages. If you double quote the
$packsthen it will throw an error.
Unquoetd
$packsis sending all the space separated package names as arguments toapt-get, while quoting it will send the$packsstring as a single argument and thenapt-getwill try to install a package namedapache2 php php-mbstring php-mysql(for the first one) which obviously doesn't exist
See what, when and why for the basics.
