How can we fetch a substring from a string in bash using scripting language?
Example:
fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
The substring I want is everything before ".URL" in the full string.
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6 Answers
With Parameter Expansion, you can do:
fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
echo ${fullstring%\.URL*}
prints:
mnuLOCNMOD
7 Comments
Maroun
I like this solution.
shraddha agrawal
how shall I use this in .sh file
P.P
@shraddhaagrawal If you mean, how to assign it then, you can do:
substring=${fullstring%\.URL*}shraddha agrawal
it is not working also with substring=
echo ${fullstring%\.URL*} it is not working in my .sh file otherwise it is working in bash shell
mklement0
Please double-quote the variable reference to promote good habits. While
\. to produce a literal . does work in this case, it is not necessary and can mislead people to think that . is special in a parameter expansion, which it isn't. The suffix to strip is a pattern, not a regex; thus: echo "${fullstring%.URL*}" will do. In Bash, the conceptually clearest formulation would be to selectively single-quote the parts to be taken literally: echo "${fullstring%'.URL'*}" |
$ fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
$ sed -r 's/^(.*)\.URL.*$/\1/g' <<< "$fullstring"
mnuLOCNMOD
$
Comments
You can use grep:
echo "mnuLOCNMOD.URL = javas" | grep -oP '\w+(?=\.URL)'
and assign the result to a string. I used a positive lookahead (?=regex) because it's a zero length assertion, meaning that it'll be matched but won't be displayed.
Run grep --help to find out what o and P flags stand for.
4 Comments
shraddha agrawal
Usage: grep -hblcnsviw pattern file . . .
shraddha agrawal
-o and P are not supported
Maroun
@shraddhaagrawal are not supported where?
Benjamin W.
@shraddhaagrawal Are you on a Solaris system?
Parameter Expansion is the way to go.
If you are interested in a simple grep:
% fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
% grep -o '^[^.]*' <<<"$fullstring"
mnuLOCNMOD
Comments
fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
menuID=`echo $fullstring | cut -f 1 -d '.'`
here I used dot as a separator this works in .sh files
1 Comment
mklement0
Yes, this is POSIX-compliant, but it is also far less restrictive than what you asked for; if you really wanted to match before
.URL specifically (and ignore other . instances), this would not work. If you only care about the first ., whatever it is followed by, you should have phrased your question like that.To offer yet another alternative: Bash's regular-expression matching operator, =~:
fullstring="mnuLOCNMOD.URL = javascript:parent.doC...something"
echo "$([[ $fullstring =~ ^(.*)'.URL' ]] && echo "${BASH_REMATCH[1]}")"
Note how the (one and only) capture group ((.*)) is reported through element 1 of the special "${BASH_REMATCH[@]}" array variable.
While in this case l3x's parameter expansion solution is simpler, =~ generally offers more flexibility.
awk offers an easy solution as well:
echo "$(awk -F'\\.URL' '{ print $1 }' <<<"$fullstring")"