CODEWITHSUNDEEP
bash
Maddy
Maddy

Reputation: 1379

Extracting a value in bash

I have a bash variable with the following value assigned to it:

# echo $b
{"tid": "session", "id": "9c7decd9-29d4-4d88-8fca-56d3b7b07bd5"}

When I try to extract the UUId from the variable 'b':

# temp=$(echo $b | awk '{print $4}')   
# echo $temp
"9c7decd9-29d4-4d88-8fca-56d3b7b07bd5"}

...I get the additional flower bracket at the end. How do I just get the UUID?

Thanks!

Upvotes: 0

Views: 60

Answers (3)

tripleee
tripleee

Reputation: 189367

What you have is JSON; so use a JSON tool to manipulate it.

jq -r .id <<<"$b"

If you want to retain the quotes, drop the -r option.

Regardless of the tool you use, always put shell variables in double quotes unless you specifically require the shell to perform word splitting and wildcard expansion on the value.

The struggle to educate practitioners to use structure-aware tools for structured data has reached epic heights and continues unabated. Before you decide to use the quick and dirty approach, at least make sure you understand the dangers (technical and mental).

Upvotes: 2

anubhava
anubhava

Reputation: 785058

You can use grep -oP with a PCRE regex:

b='{"tid": "session", "id": "9c7decd9-29d4-4d88-8fca-56d3b7b07bd5"}'
temp=$(grep -oP '"id": +"\K[^"]+' <<< "$b")

echo "$temp"
9c7decd9-29d4-4d88-8fca-56d3b7b07bd5

Upvotes: 1

Karthikeyan.R.S
Karthikeyan.R.S

Reputation: 4041

Use this

 echo $b | sed 's/.*: \([^\}]*\)\}/\1/'

Or else,

 echo $b | sed 's/.*id: \([^\}]*\)\}/\1/'

Upvotes: 0

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