Extract string from brackets
Try this:
echo $str | cut -d "[" -f2 | cut -d "]" -f1
Here's one way using awk:
echo "string1 [string2] string3 string4" | awk -F'[][]' '{print $2}'
This sed option also works:
echo "string1 [string2] string3 string4" | sed 's/.*\[\([^]]*\)\].*/\1/g'
Here's a breakdown of the sed command:
s/ <-- this means it should perform a substitution
.* <-- this means match zero or more characters
\[ <-- this means match a literal [ character
\( <-- this starts saving the pattern for later use
[^]]* <-- this means match any character that is not a [ character
the outer [ and ] signify that this is a character class
having the ^ character as the first character in the class means "not"
\) <-- this closes the saving of the pattern match for later use
\] <-- this means match a literal ] character
.* <-- this means match zero or more characters
/\1 <-- this means replace everything matched with the first saved pattern
(the match between "\(" and "\)" )
/g <-- this means the substitution is global (all occurrences on the line)