CODEWITHSUNDEEP
linuxbashcentos7
Dovid Bender
Dovid Bender

Reputation: 139

Get value from string based on RegEx

I have a bash script that I am trying to learn from. I have a sql file that has in it:

create user myuser with password 'mypassword';

I want to use sed and store the value of the password in one bash variable and the pasword in another bash variable. The script that I am learning from has:

USERNAME := $(shell sed -n \
"s/^create user \(\S\+\) with password '\(\S\+\)';$$/\1/p" \
createdb.sql)
PASSWORD := $(shell sed -n \
"s/^create user \(\S\+\) with password '\(\S\+\)';$$/\2/p" \
createdb.sql)

No matter what I tried the regex would not match up. Part of my issue is I don't understand the basics of sed. How do I go about getting the value of parts of the string?

Upvotes: 0

Views: 108

Answers (1)

chepner
chepner

Reputation: 532238

Don't use sed for this; use bash's built-in regular expression support.

str="create user myuser with password 'mypassword';"
regex='create user (.*) with password (.*);'
if [[ $str =~ $regex ]]; then
    username=${BASH_REMATCH[1]}
    password=${BASH_REMATCH[2]}
fi

As for how you get the appropriate line in the first place, use grep:

str=$(grep "create user" createddb.sql)

Upvotes: 2

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