Special Parameters ($@ and $*)

• $@ is used to manipulate all the arguments passed to the shell while running as each item considered as SEPARATE item.
• $* is used to manipulate all the arguments passed to the shell while running as each item considered as ONE item.

$@ without quotes

This will loop through all the items individually like below

#!/bin/bash
for item in $@
do
  echo "${item}"
done

$@ with quotes

This will loop through all the items individually like below

#!/bin/bash
for item in "$@"
do
  echo "${item}"
done

$@ behaves same with quotes or without quotes. Remember there is NO custom IFS

$@ without quotes along with IFS(Custom Separator)

This will loop through all the items individually like below

#!/bin/bash
IFS=","
for item in $@
do
  echo "${item}"
done

$@ with quotes along with IFS

This will loop through all the items at once like below

#!/bin/bash
IFS=","
for item in "$@"
do
  echo "${item}"
done

$@ behaves differently with quotes or without quotes when custom IFS involves.

- With quotes + custom IFS, it considered as ONE word

- Without quotes + custom IFS, it is considered as SEPARATE word

CONCLUSION for $@

Without quotes

- $@ will split the item INDIVIDUALLY, Doesn't matter if custom IFS is there or not

With quotes

- $@ will split the item INDIVIDUALLY when if custom IFS is not involved

- $@ will NOT split the item INDIVIDUALLY when if custom IFS is involved

$* without quotes

This will loop through all the items individually like below

#!/bin/bash
for item in $*
do
  echo "${item}"
done

$* with quotes

This will loop through all the items individually like below

#!/bin/bash
for item in "$*"
do
  echo "${item}"
done

$* behaves differently with quotes or without quotes.

• With quotes, it considered as ONE word
• Without quotes, it is considered as SEPARATE word

$* without quotes along with IFS(Custom Separator)

#!/bin/bash
IFS=","
for item in $*
do
  echo "${item}"
done

$* with quotes along with IFS

This will loop through all the items at once like below

#!/bin/bash
IFS=","
for item in "$*"
do
  echo "${item}"
done

$* behaves differently with quotes or without quotes when custom IFS involves.

- With quotes + custom IFS, it considered as ONE word

- Without quotes + custom IFS, it is considered as SEPARATE word

CONCLUSION for $*

Without quotes

- $* will split the item INDIVIDUALLY, Doesn't matter if custom IFS is there or not

With quotes

- $* will NOT split the item, Doesn't matter if custom IFS is there or not