Extract string from brackets

Question

I\'m pretty new at bash so this is a pretty noob question..

Suppose I have a string:

string1 [string2] string3 string4

I would like

Answer 1

Another awk:

$ echo "string1 [string2] string3 [string4]" |
awk -v RS=[ -v FS=] 'NR>1{print $1}' 
string2
string4

Answer 2

In pure bash:

STR="string1 [string2] string3 string4"
STR=${STR#*[}
STR=${STR%]*}
echo $STR

Answer 3

Inline solution could be:

a="first \"Foo1\" and second \"Foo2\""
echo ${a#*\"} | { read b; echo ${b%%\"*}; }

You can test in single line:

a="first \"Foo1\" and second \"Foo2\""; echo ${a#*\"} | { read b; echo ${b%%\"*}; }

Output: Foo1

Example with brackets:

a="first [Foo1] and second [Foo2]"
echo ${a#*[} | { read b; echo ${b%%]*}; }

That in one line:

a="first [Foo1] and second [Foo2]"; echo ${a#*[} | { read b; echo ${b%%]*}; }

Output: Foo1