I have a list of URLS that I need to check, to see if they still work or not. I would like to write a bash script that does that for me.
I only need the returned HTTP status code, i.e. 200, 404, 500 and so forth. Nothing more.
Hi Julien, Thanks for reply. 1 I'm exchange with network team, but for some security principles, they are (logically) not very open to open some specific urls (because it is an anonymous door for some hacks. Even if in this case it's fetched). The library used by the uri module only sends authentication information when a webservice responds to an initial request with a 401 status. Since some basic auth services do not properly send a 401, logins will fail. This option forces the sending of the Basic authentication header upon initial request.
EDIT Note that there is an issue if the page says '404 not found' but returns a 200 OK message. It's a misconfigured web server, but you may have to consider this case.
For more on this, see Check if a URL goes to a page containing the text '404'
codeforester6 Answers
Curl has a specific option, --write-out
, for this:
-o /dev/null
throws away the usual output--silent
throws away the progress meter--head
makes a HEAD HTTP request, instead of GET--write-out '%{http_code}n'
prints the required status code
To wrap this up in a complete Bash script:
(Eagle-eyed readers will notice that this uses one curl process per URL, which imposes fork and TCP connection penalties. It would be faster if multiple URLs were combined in a single curl, but there isn't space to write out the monsterous repetition of options that curl requires to do this.)
PhilPhilExtending the answer already provided by Phil. Adding parallelism to it is a no brainer in bash if you use xargs for the call.
Here the code:
-n1: use just one value (from the list) as argument to the curl call
-P10: Keep 10 curl processes alive at any time (i.e. 10 parallel connections)
Check the write_out
parameter in the manual of curl for more data you can extract using it (times, etc).
In case it helps someone this is the call I'm currently using:
It just outputs a bunch of data into a csv file that can be imported into any office tool.
estaniestaniUse curl
to fetch the HTTP-header only (not the whole file) and parse it:
wget -S -i *file*
will get you the headers from each url in a file.
Filter though grep
for the status code specifically.
This relies on widely available wget
, present almost everywhere, even on Alpine Linux.
The explanations are as follow :
--quiet
Turn off Wget's output.
Source - wget man pages
--spider
[ ... ] it will not download the pages, just check that they are there. [ ... ]
Source - wget man pages
--server-response
Print the headers sent by HTTP servers and responses sent by FTP servers.
Source - wget man pages
What they don't say about --server-response
is that those headers output are printed to standard error (sterr), thus the need to redirect to stdin.
The output sent to standard input, we can pipe it to awk
to extract the HTTP status code. That code is :
- the second (
$2
) non-blank group of characters:{$2}
- on the very first line of the header:
NR1
And because we want to print it... {print $2}
.
protected by codeforesterNov 18 '18 at 7:14
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