Pipe curl to stdout

By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. It only takes a minute to sign up. I need to retrieve the expiry date of an SSL cert. The curl application does provide this information:.

Redirection Operatros and STDIN, STDOUT & STDERR

However, when piping the output via grep the result is not less information on the screen, but rather much more :. I suspect that curl detects that it is not printing to a terminal and is thus gives different output, not all of which is recognized by grep as being stdout and is thus passed through to the terminal.

However, the closest thing to this that I could find in man curl don't ever google for that! How can I get just the expiry line out of the curl output? Furthermore, what should I be reading to understand the situation better? Seems like this would be a good use case for a "stdmeta" file descriptor. It is possible to use --stderr - as parameter, to redirect the output from stderr default to stdout. With this option you also should use --silent to suppress the progress bar.

Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How to grep the output of cURL?

Ask Question. Asked 5 years, 5 months ago. Active 1 year, 6 months ago. Viewed k times.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service.

The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Curl documentation for -d option. If you start the data with the letterthe rest should be a file name to read the data from, or - if you want curl to read the data from stdin. Multiple files can also be specified. Posting data from a file named 'foobar' would thus be done with -d, --data foobar.

When --data is told to read from a file like that, carriage returns and newlines will be stripped out. If you don't want the character to have a special interpretation use --data-raw instead. Which drops you into cat where you can input the data, directly, e.

How to Grep the Output of Curl Command

That data is then passed to curl, and you have a reusable history entry. See jq manual for full details. I think that the simplest way to do that is to manipulate stdin first and then push that over to curl using -d. One way could look like this:.

Keep in mind that this does not escape the contents of file and that you may run into issues because of that. Learn more. Asked 7 years, 6 months ago. Active 3 months ago. Viewed 42k times. Peter Turner I'm not sure if there is a special format here, otherwise this might be what you want: serverfault. Active Oldest Votes. I spent a while trying to figure this out and got it working with the following: cat data. Tom Jowitt Tom Jowitt 4, 9 9 gold badges 40 40 silver badges 55 55 bronze badges.

Nathan Nathan 3 3 silver badges 8 8 bronze badges. Beware of string substitution, especially for binary data. This may subtly corrupt your data e. Joe King Joe King 4, 1 1 gold badge 24 24 silver badges 31 31 bronze badges. Very good for use cases where the size of the data exceeds what bash arguments can handle. Curl documentation for -d option If you start the data with the letterthe rest should be a file name to read the data from, or - if you want curl to read the data from stdin.

pipe curl to stdout

Depending of your HTTP endpoint, server configuration, you should be good by using this format: curl -d data. Walf Walf 5, 2 2 gold badges 29 29 silver badges 46 46 bronze badges.

Notice that the contents of the input file was properly escaped for using as a JSON value. Robin A. Meade Robin A. Meade 7 7 silver badges 12 12 bronze badges. Sign up or log in Sign up using Google. Sign up using Facebook.

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It only takes a minute to sign up. I am trying to download some. However, this did not work as it failed with: gzip: stdin: unexpected end of file.

I ran a series of this command inside a bash shell script. If I spilt the command into two explicit steps, i.

A pipe represented by the symbol sends the standard output of one process to the standard input of another. In your case, you appear to want to use a named file so a pipe is not appropriate - specifically, there is nothing to pipe hence the gunzip error because the remote contents are going to a local file.

Instead, you'd need to extract the name of the file - for example, from its URL - something like using bash's built in string manipulation capabilities. Follow redirects when downloading.

If you don't follow the redirect, the wrong data gets downloaded and your application reading the piped data gets confused.

You can follow redirects with curl using the -L flag. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top.

Pipes, redirection, and standard out and in

Home Questions Tags Users Unanswered. Asked 5 years, 5 months ago. Active 20 days ago. Viewed 12k times. Why the piped version does not work? Are you sure that curl -O actually streams the file to standard output? Perhaps you are thinking of wget -O-? There is also --compressedbut this works only for a compressed responses.

Active Oldest Votes. Jam Risser Jam Risser 2 2 silver badges 3 3 bronze badges.Curl is a utility that allows you to transfer data to or from a server using many different protocols. It is most commonly use to fetch web pages or information from the web to the Linux command line.

In this Linux quick tip we will show you how to grep the output of the curl command. This comes in especially handy when you are using verbose mode to capture data like cookies, protocols, and header information.

If you attempt to pipe the output of the curl command to grep you will get an unexpected result. Basically, the grep command will be ignored and you will see the full output of curl. Once you redirect the standard error stream to standard output you can use grep as you normally would.

If you specify the filename as - a single dash the output will be written to standard output. This allows you to pipe it to grep without any shell redirection. Once you understand standard streams and redirection this workaround will seem natural.

This is not normal behavior for a command line utility. Username or Email Address. Remember Me. Sign Up For Our Newsletter. If you continue to browse or click Accept, you agree to the storing of cookies on your device. To learn more about why we use cookies, please see our cookie policy. Linux Quick Tips. Marco CherisiJanuary 29, 2 min read. Jump directly to " How to grep curl output " The Problem with Using Grep on Curl Output If you attempt to pipe the output of the curl command to grep you will get an unexpected result.

Let's look at two methods for capturing the curl output and piping it to grep.

pipe curl to stdout

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Server Fault is a question and answer site for system and network administrators. It only takes a minute to sign up. How is it possible to pipe out wget 's downloaded file? If not what alternatives should I use? Just to add another option: I often use lwp-request, from libwww-perl, for this.

I suggest to use Aria2. It's powerful downloader. Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered.

How do I pipe a downloaded file to standard output in bash? Ask Question. Asked 10 years, 10 months ago. Active 4 years, 2 months ago. Viewed 45k times. Alex Alex 2, 5 5 gold badges 27 27 silver badges 41 41 bronze badges. Active Oldest Votes. Or use curl, where it's the default behaviour. GodEater GodEater 1 1 gold badge 6 6 silver badges 12 12 bronze badges. David Pashley David Pashley Offtopic, but I've used lynx in some of my scripts to parse html for me automatically whenever I've needed the content of a page and didn't care about the markup.

I prefer w3m for its table and frame support. Jeff Tang Jeff Tang 2 2 bronze badges. Not sure if Perl is more common than curl. Roger Roger 10 10 silver badges 22 22 bronze badges. Phil Huang Phil Huang 11 2 2 bronze badges. The Overflow Blog. The Overflow How many jobs can be done at home? Featured on Meta.

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The dark mode beta is finally here. Change your preferences any time. Stack Overflow for Teams is a private, secure spot for you and your coworkers to find and share information. Is there a way to get around this?

pipe curl to stdout

Why is this happening? Your URL probably has ampersands in it. I had this problem, too, and I realized that my URL was full of ampersands from CGI variables being passed and so everything was getting sent to background in a weird way and thus not redirecting properly.

If you put quotes around the URL it will fix it. But then, as pointed out in the comments, it also works without the xargs part, so -s silent mode is the key to preventing extraneous progress output to STDOUT:.

Learn more. How do I pipe or redirect the output of curl -v? Ask Question. Asked 9 years ago. Active 1 year, 10 months ago. Viewed k times. Active Oldest Votes.

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SingleNegationElimination SingleNegationElimination k 21 21 gold badges silver badges bronze badges. The full output including headers is still displayed on the console. Is there some other stream that I can pipe into grep to extract some data that I need?

What information are you actually trying to extract, and what information do you want to throw away. I understood your question to mean that you want all of the output of -v directed to stdout.

I want to process some of the cookies basically grep some info from the cookies and do some other stuff. Yes, I want everything to go to std out, so I can process whatever I want via pipes. Currently some of the output just displays on the console and seems impossible to redirect and I'm not sure why. Can you post a screenshot of the output appearing on screen that you wish to capture? It's just the same type of output as with any other website.

The only difference is that the server is running locally. I had the same problem. Thanks roadnottaken. Love Stack-O I found this q, and the mention of ampersands in the URL.

It put quotes around mine, and problem solved. The quotes did the trick for me.By using our site, you acknowledge that you have read and understand our Cookie PolicyPrivacy Policyand our Terms of Service. Ask Ubuntu is a question and answer site for Ubuntu users and developers. It only takes a minute to sign up. When I curl a file, and pipe it to a file or another command, I see output in my terminal.

I am not sure how this happens, as the pipe is supposed to take all the output from curl, right? However, showing how to redirect both streams added to the answer, so don't remove that. There are two output streams generally available: standard output, and standard error.

In practice, when running in a terminal, both send data to the terminal. To suppress both, use one of:. Curl should use a way to show these two separately otherwise processing of the real output URL's content would be hard and I'll end up with unnecessary contents curl's status. Ubuntu Community Ask! Sign up to join this community. The best answers are voted up and rise to the top. Home Questions Tags Users Unanswered. How does curl print to terminal while piping Ask Question. Asked 2 years, 8 months ago.

Active 1 year, 7 months ago. Viewed 11k times. Ravexina See superuser. I'm asking because the answers so far all feature how to redirect its standard output and standard error streams together.

But if you're using curl to download files on standard output, you do not want to redirect stdout and stderr to the same place--any output on stderr would corrupt the download! I know you've already accepted an answer, but would you be willing to edit this with an example of how you're using curl?

I think that would make this question more valuable to future readers in similar situations. EliahKagan Sure, thanks for the suggestion. Maybe you want to do this? Active Oldest Votes. To suppress both, use one of: curl Don't show progress meter or error messages. To send both to a pipe: curl Also see: Stack Overflow: confused about stdin, stdout and stderr? When you are using curl to open an URL, you'll get two output: The status of the curl itself.

The contents of that URL. So it uses stderr for its status and stdout for the content. Ravexina Ravexina Sign up or log in Sign up using Google. Sign up using Facebook. Sign up using Email and Password. Post as a guest Name.


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