What is the difference between =
and ==
to compare strings in Linux shell programming?
Maybe the following code works:
if [ \"$
you can take a look here or here. Personally, to compare strings, I use case
case "$string1" in
"$string2" ) echo "matched";;
*) echo "not matched";;
esac
I do not have to know which operator i should use
In general, the = operator works the same as == when comparing strings.
Note: The == comparison operator behaves differently within a double-brackets test than within single brackets.
[[ $a == z* ]] # True if $a starts with an "z" (pattern matching).
[[ $a == "z*" ]] # True if $a is equal to z* (literal matching).
[ $a == z* ] # File globbing and word splitting take place.
[ "$a" == "z*" ] # True if $a is equal to z* (literal matching).
source: http://tldp.org/LDP/abs/html/comparison-ops.html
The single equal is correct
string1 == string2
string1 = string2
True if the strings are equal. ‘=’ should be used with the test command for POSIX conformance
NAME="rafael"
USER="rafael"
if [ "$NAME" = "$USER" ]; then
echo "Hello"
fi
These pages explain the various comparison operators in bash:
On the second linked page, you will find:
==
is equal to
if [ "$a" == "$b" ]
This is a synonym for =.