重击多变量分配

Question

Objective

Assign HTTP status code and date from cURL output to RESP and DATE variables using one-liner command.

Expectation

[08 Nov 2017 19:28:44 GMT] 301

Reality

$ read -d "\n" RESP DATE <<< $(curl -sv https://google.com 2>&1 | egrep -i "< HTTP/2|< Date" | sed "s/< HTTP\/2 //;s/< date: //g"); echo "[$DATE] $RESP"
[
] 30108 Nov 2017 19:28:44 GMT
$

EDIT:

Here's the full working command:

$ read -d "\r" RESP DATE <<< $(curl -sv https://google.com 2>&1 | tr -d "\r" | egrep -i "< HTTP/2|< Date" | sed "s/< HTTP\/2 //;s/< date: //g"); echo "[$DATE] $RESP"
[Wed, 08 Nov 2017 19:57:33 GMT] 301
$

Answer 1

The output of curl contains some \\r characters, that's why the output looks messed up. You can get rid of it by inserting a tr -d '\\r' into the pipeline after the curl and before the egrep .

Is it really important to read into RESP and DATE variables? You could use Awk to extract the interesting parts simpler, saner, and output directly in the desired format:

curl ... | tr -d '\r' | awk '/^< Date: / { date = substr($0, 9); print "[" date "] " resp } /^< HTTP\// { resp = $3 }'

Answer 2

How about awk:

curl --silent --head https://google.com | awk '
    /^HTTP/ {code = $2} 
    /^Date:/ {
        sub(/\r$/,"")
        date = substr($0,7)
        printf "[%s] %s\n", date, code
        exit
    }
'

Using an HTTP HEAD request to minimize traffic.