如何在Bash命令行中使用grep捕获特定文本？

Question

我需要在Bash命令行上使用grep捕获特定的字符串。我不能使用sudo install / apt-install来安装任何附加软件/软件包，例如jq。我没有使用任何Python解释器；只是Bash命令行。

我在在线正则表达式测试仪上用所需的输入字符串测试了我的正则表达式字符串，并且可以正常工作。但是，当我使用grep尝试时，它会提供整个文本，而不是捕获的文本。

正则表达式：'":"(.+)","'

输入：

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

获得的结果：

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

预期：

eyJhbGciOiJSUzI1NiIsImtpZCI6IkE4M0UwQTFEQTY1MzE0NkZENUQxOTFDMzRDNTQ0RDJDODYyMzMzMzkiLCJ0eXAiOiJKV1QiLCJ4NXQiOiJxRDRLSGFaVEZHX1YwWkhEVEZSTkxJWWpNemsifQ.eyJuYmYiOjE1NTkzMjk5OTIsImV4cCI6MTU1OTMzMzU5MiwiaXNzIjoiaHR0cHM6Ly9jaW5jaHktbnByLmNsb3VkLnJlcy5ibmdmLmxvY2FsL2NpbmNoeXNzbyIsImF1ZCI6WyJodHRwczovL2NpbmNoeS1ucHIuY2xvdWQucmVzLmJuZ2YubG9jYWwvY2luY2h5c3NvL3Jlc291cmNlcyIsImpzX2FwaSJdLCJjbGllbnRfaWQiOiJhcGkiLCJzdWIiOiIxIiwiYXV0aF90aW1lIjoxNTU5MzI5OTkyLCJpZHAiOiJsb2NhbCIsInByb2ZpbGUiOiJBZG1pbmlzdHJhdG9yIiwiZW1haWwiOiJhZG1pbkBjaW5jaHkuY28iLCJyb2xlIjoiQ2luY2h5IFVzZXIgQWNjb3VudCIsImlkIjoiYWRtaW4iLCJzY29wZSI6WyJqc19hcGkiXSwiYW1yIjpbImN1c3RvbSJdfQ.gI_MYzkanGmDXPd8Wp1Q2XOOhAvnWxzOxSUngxYv8UFO1ozXm5ZxFDpUVXFodTQHKEk2B9h9VMXwyg80bxqqT7csHnjg43tylgEIKpupcubqXT1HzH_bMv8povGU6S75b8p8SWQKyYihm4nBdMDJFZMtKMg95ByBlaHpXV_6vuLUB0qFfcbWi5rHgHnJOT08ZJcHJUozS05FVZt_lU2zepNrwSqOvY3AnXpz9Z8KfrlARB46ukB3tBJzNvMDvxi44wfwpnky-4dxq0CcHoa766l6E66gjaLmR3ApHy4YKnP_DxDSR6mSHnVTEzPN7mt_1rklseK0TVd0kK3CpUg2aQ

Answer 1

如果没有更合适的工具（例如jq），则使用GNU grep和与Perl兼容的正则表达式（PCRE）：

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