I am creating a script, which should download latest version of an application from repository and deploy the app.

The main issue: there are several repositories and I need to check, which of them has most recent version.


http://repo1/xyz/LATEST -> (redirects to) -> http://repo1/xyz/app-
http://repo2/xyz/LATEST -> (redirects to) -> http://repo1/xyz/app-

So I need to iterate over available repositories and get only a filename - no need to download obsolette versions of software.

2 Answers 2


Something like this could work for you:

curl -sIkL http://repo1/xyz/LATEST | sed -r '/filename=/!d;s/.*filename=(.*)$/\1/'

Take a look at man page curl(1) for the options. The interesting one is -I, --head.

Explanation as requested per comments:

The idea is to request the HTTP response header only.

Therefore the -I options is used. -s silents curl to not print anything else than the header. -k allows "insecure" SSL connections (curl would reject self-signed certs otherwise). And -L to follow HTTP(S) location redirects.

Then sed(1) is used to get the file name from response header. We are searching for the filename= field, so the /filename=/!d part removes anything without that field from output. Finally the s/.*filename=(.*)$/\1/ part prints the file name only if the field is found.

  • 1
    Your answer would be more useful if you shortly explain -I here. Also, what is you sed command supposed to do?
    – Bernhard
    Apr 24, 2014 at 7:50
  • CooL! Needs few upgrades, but general idea is very helpful. Apr 24, 2014 at 7:51
  • I echo Bernhard's comment - by explaining what the different elements in your response do, you will help people who want to do something similar to the OP but not exactly the same. Apr 24, 2014 at 7:57

I came out with this solution, quite similar to the one by @FloHimself.

curl -L --head http://repo1/xyz/LATEST 2>/dev/null | grep Location: | tail -n1 | cut -d' ' -f2
  • -L lets curl follows the redirection
  • --head makes it fetch only the headers and not the pages' content.
  • grep Location: looks for the Location: header in 30x HTTP responses by the server
  • tail -n1 selects the last one
  • cut -d' ' -f2 selects the second field (the URL)

The same, but letting curl do all the work:

curl -L --head -w '%{url_effective}' http://repo1/xyz/LATEST  2>/dev/null | tail -n1

This solution use the -w, --write-out option to ask curl for a specific output. man curl gives the available variables.

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