Quote:
Originally Posted by vino
You will not find any difference between those two grep's. Rather try these two and see the difference.
grep '$USER' /etc/passwd
grep "$USER" /etc/passwd
Open the man pages of sh or ksh and see the section on Quoting. Basically single quotes prevent variable expansion.
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Adding to Vino's comment...
variables in single quotes are treated as const. string
as
1. var = 5 ;
echo '$var'
This will simply display the string $var as it is, no variable replacement by value.
2. var = 5;
echo "$var"
In double quotes variables get expansion in terms of its value.
o/p will be 5
Similarly is the case with grep '$var' and grep "$var".
But when it comes to constant string, it hardly reflects any change.
grep -w "string1 string2" file1
grep -w 'string1 string2" file1
Both are same.
Hope you get this !!
