CODEWITHSUNDEEP
bashshell
Joly
Joly

Reputation: 3276

Extract substrings from a String

I'm new to shell programming.

I have a String representation of a db connection looking like that:

<user>:<password>@<host>

And I would like to extract each attribute (user, password and host) from the String.

Upvotes: 1

Views: 212

Answers (2)

lessyv
lessyv

Reputation: 116

Bash string manipulation can be done as follow:

input="<user>:<password>@<host>"
colonPos=$(expr index "${input}" ':')
atPos=$(expr index "${input}" '@')
user=${input:0:$colonPos-1}
pass=${input:$colonPos:$atPos-$colonPos-1}
host=${input:$atPos}
echo -e "input: ${input}\nuser: ${user}\npass: ${pass}\nhost: ${host}"

It also doesn't works with many : and/or @, but you can play with:

tmpStr="${input//[^\:]/}"
colonAmount=${#tmpStr}
tmpStr="${input//[^@]/}"
atAmount=${#tmpStr}
echo -e "colon(s) amount: ${colonAmount}\nat(s) amount: ${atAmount}"

Let's play with if then elif else fi using those *Amount variables to develop your own parser in bash !

Upvotes: 0

FatalError
FatalError

Reputation: 54551

A naive way to do it would be:

$ IFS=:@ read -a args <<< "<user>:<password>@<host>"
$ echo ${args[0]}
<user>
$ echo ${args[1]}
<password>
$ echo ${args[2]}
<host>

Obviously, this won't work if the username or password can contain a ':' or '@' character, or if your host happens to be an IPv6 address ;).

Upvotes: 3

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