How to capture specific text with grep, in Bash Command Line?

Question

I need to capture a specific string using grep, on Bash Command Line. I cannot use sudo install/apt-install to install any addition software/packages like jq. I am not using any Python Interpreter; simply Bash Command Line.

I tested my regex string with the desired input string on an online regex tester, and it works. Yet when I try it with grep, it provides me the whole text, and not the captured text.

Regex: '":"(.+)","'

Input:

HTTP_RESPONSE='{"access_token":"eyJhbGciOiJSUzI1NiIsImtpZCI6IkE4M0UwQTFEQTY1MzE0NkZENUQxOTFDMzRDNTQ0RDJDODYyMzMzMzkiLCJ0eXAiOiJKV1QiLCJ4NXQiOiJxRDRLSGFaVEZHX1YwWkhEVEZSTkxJWWpNemsifQ.eyJuYmYiOjE1NTkzMjk5OTIsImV4cCI6MTU1OTMzMzU5MiwiaXNzIjoiaHR0cHM6Ly9jaW5jaHktbnByLmNsb3VkLnJlcy5ibmdmLmxvY2FsL2NpbmNoeXNzbyIsImF1ZCI6WyJodHRwczovL2NpbmNoeS1ucHIuY2xvdWQucmVzLmJuZ2YubG9jYWwvY2luY2h5c3NvL3Jlc291cmNlcyIsImpzX2FwaSJdLCJjbGllbnRfaWQiOiJhcGkiLCJzdWIiOiIxIiwiYXV0aF90aW1lIjoxNTU5MzI5OTkyLCJpZHAiOiJsb2NhbCIsInByb2ZpbGUiOiJBZG1pbmlzdHJhdG9yIiwiZW1haWwiOiJhZG1pbkBjaW5jaHkuY28iLCJyb2xlIjoiQ2luY2h5IFVzZXIgQWNjb3VudCIsImlkIjoiYWRtaW4iLCJzY29wZSI6WyJqc19hcGkiXSwiYW1yIjpbImN1c3RvbSJdfQ.gI_MYzkanGmDXPd8Wp1Q2XOOhAvnWxzOxSUngxYv8UFO1ozXm5ZxFDpUVXFodTQHKEk2B9h9VMXwyg80bxqqT7csHnjg43tylgEIKpupcubqXT1HzH_bMv8povGU6S75b8p8SWQKyYihm4nBdMDJFZMtKMg95ByBlaHpXV_6vuLUB0qFfcbWi5rHgHnJOT08ZJcHJUozS05FVZt_lU2zepNrwSqOvY3AnXpz9Z8KfrlARB46ukB3tBJzNvMDvxi44wfwpnky-4dxq0CcHoa766l6E66gjaLmR3ApHy4YKnP_DxDSR6mSHnVTEzPN7mt_1rklseK0TVd0kK3CpUg2aQ","expires_in":3600,"token_type":"Bearer"}'
echo $HTTP_RESPONSE | grep -E '":"(.+)","'

Obtained Result:

{"access_token":"eyJhbGciOiJSUzI1NiIsImtpZCI6IkE4M0UwQTFEQTY1MzE0NkZENUQxOTFDMzRDNTQ0RDJDODYyMzMzMzkiLCJ0eXAiOiJKV1QiLCJ4NXQiOiJxRDRLSGFaVEZHX1YwWkhEVEZSTkxJWWpNemsifQ.eyJuYmYiOjE1NTkzMjk5OTIsImV4cCI6MTU1OTMzMzU5MiwiaXNzIjoiaHR0cHM6Ly9jaW5jaHktbnByLmNsb3VkLnJlcy5ibmdmLmxvY2FsL2NpbmNoeXNzbyIsImF1ZCI6WyJodHRwczovL2NpbmNoeS1ucHIuY2xvdWQucmVzLmJuZ2YubG9jYWwvY2luY2h5c3NvL3Jlc291cmNlcyIsImpzX2FwaSJdLCJjbGllbnRfaWQiOiJhcGkiLCJzdWIiOiIxIiwiYXV0aF90aW1lIjoxNTU5MzI5OTkyLCJpZHAiOiJsb2NhbCIsInByb2ZpbGUiOiJBZG1pbmlzdHJhdG9yIiwiZW1haWwiOiJhZG1pbkBjaW5jaHkuY28iLCJyb2xlIjoiQ2luY2h5IFVzZXIgQWNjb3VudCIsImlkIjoiYWRtaW4iLCJzY29wZSI6WyJqc19hcGkiXSwiYW1yIjpbImN1c3RvbSJdfQ.gI_MYzkanGmDXPd8Wp1Q2XOOhAvnWxzOxSUngxYv8UFO1ozXm5ZxFDpUVXFodTQHKEk2B9h9VMXwyg80bxqqT7csHnjg43tylgEIKpupcubqXT1HzH_bMv8povGU6S75b8p8SWQKyYihm4nBdMDJFZMtKMg95ByBlaHpXV_6vuLUB0qFfcbWi5rHgHnJOT08ZJcHJUozS05FVZt_lU2zepNrwSqOvY3AnXpz9Z8KfrlARB46ukB3tBJzNvMDvxi44wfwpnky-4dxq0CcHoa766l6E66gjaLmR3ApHy4YKnP_DxDSR6mSHnVTEzPN7mt_1rklseK0TVd0kK3CpUg2aQ","expires_in":3600,"token_type":"Bearer"}

Expected:

eyJhbGciOiJSUzI1NiIsImtpZCI6IkE4M0UwQTFEQTY1MzE0NkZENUQxOTFDMzRDNTQ0RDJDODYyMzMzMzkiLCJ0eXAiOiJKV1QiLCJ4NXQiOiJxRDRLSGFaVEZHX1YwWkhEVEZSTkxJWWpNemsifQ.eyJuYmYiOjE1NTkzMjk5OTIsImV4cCI6MTU1OTMzMzU5MiwiaXNzIjoiaHR0cHM6Ly9jaW5jaHktbnByLmNsb3VkLnJlcy5ibmdmLmxvY2FsL2NpbmNoeXNzbyIsImF1ZCI6WyJodHRwczovL2NpbmNoeS1ucHIuY2xvdWQucmVzLmJuZ2YubG9jYWwvY2luY2h5c3NvL3Jlc291cmNlcyIsImpzX2FwaSJdLCJjbGllbnRfaWQiOiJhcGkiLCJzdWIiOiIxIiwiYXV0aF90aW1lIjoxNTU5MzI5OTkyLCJpZHAiOiJsb2NhbCIsInByb2ZpbGUiOiJBZG1pbmlzdHJhdG9yIiwiZW1haWwiOiJhZG1pbkBjaW5jaHkuY28iLCJyb2xlIjoiQ2luY2h5IFVzZXIgQWNjb3VudCIsImlkIjoiYWRtaW4iLCJzY29wZSI6WyJqc19hcGkiXSwiYW1yIjpbImN1c3RvbSJdfQ.gI_MYzkanGmDXPd8Wp1Q2XOOhAvnWxzOxSUngxYv8UFO1ozXm5ZxFDpUVXFodTQHKEk2B9h9VMXwyg80bxqqT7csHnjg43tylgEIKpupcubqXT1HzH_bMv8povGU6S75b8p8SWQKyYihm4nBdMDJFZMtKMg95ByBlaHpXV_6vuLUB0qFfcbWi5rHgHnJOT08ZJcHJUozS05FVZt_lU2zepNrwSqOvY3AnXpz9Z8KfrlARB46ukB3tBJzNvMDvxi44wfwpnky-4dxq0CcHoa766l6E66gjaLmR3ApHy4YKnP_DxDSR6mSHnVTEzPN7mt_1rklseK0TVd0kK3CpUg2aQ

https://stackoverflow.com/questions/56400188/how-to-get-the-value-of-a-key-in-a-json#comment99399706_56400188 — Cyrus, Jun 02 '19 at 17:56
@Cyrus the question continued to be unanswered so I opened another post, with better details and stricter details. — codermonkey321, Jun 02 '19 at 18:01

score 0 · Accepted Answer · answered Jun 02 '19 at 18:00

0

With GNU grep and Perl-compatible regular expression (PCRE), if no more suitable tool (jq, e.g.) is available:

echo "$HTTP_RESPONSE" | grep -oP '(?<="access_token":").*?(?=")'

answered Jun 02 '19 at 18:00

Cyrus

84,225
14
89
153

How to capture specific text with grep, in Bash Command Line?

1 Answers1