Execute bash script from URL

Question

Say I have a file at the URL http://mywebsite.example/myscript.txt that contains a script:

#!/bin/bash
echo "Hello, world!"
read -p "What is your name? " name
echo "Hello, ${name}!"

And I'd like to run this script without first saving it to a file. How do I do this?

Now, I've seen the syntax:

bash < <(curl -s http://mywebsite.example/myscript.txt)

But this doesn't seem to work like it would if I saved to a file and then executed. For example readline doesn't work, and the output is just:

$ bash < <(curl -s http://mywebsite.example/myscript.txt)
Hello, world!

Similarly, I've tried:

curl -s http://mywebsite.example/myscript.txt | bash -s --

With the same results.

Originally I had a solution like:

timestamp=`date +%Y%m%d%H%M%S`
curl -s http://mywebsite.example/myscript.txt -o /tmp/.myscript.${timestamp}.tmp
bash /tmp/.myscript.${timestamp}.tmp
rm -f /tmp/.myscript.${timestamp}.tmp

But this seems sloppy, and I'd like a more elegant solution.

I'm aware of the security issues regarding running a shell script from a URL, but let's ignore all of that for right now.

If you do end up creating a temporary file, you should probably be using mktemp instead of rolling your own solution — Hasturkun
– Hasturkun, Commented Apr 20, 2011 at 19:44
cmd <<foo is heredoc syntax in most shells and probably not what you want. — iteratingself
– iteratingself, Commented Apr 20, 2011 at 20:52

Stephen Ostermiller · Accepted Answer · 2022-06-23 19:50:23Z

298

source <(curl -s http://mywebsite.example/myscript.txt)

ought to do it. Alternately, leave off the initial redirection on yours, which is redirecting standard input; bash takes a filename to execute just fine without redirection, and <(command) syntax provides a path.

bash <(curl -s http://mywebsite.example/myscript.txt)

It may be clearer if you look at the output of echo <(cat /dev/null)

edited Jun 23, 2022 at 19:50

Stephen Ostermiller♦

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answered Apr 20, 2011 at 19:45

geekosaur

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11 Comments

Tristan Over a year ago

Thanks, this made it clear what was going on. Just curious, what is the advantage of using that initial redirection? I ask because for RVM installation, they use the command: bash < <(curl -s https://rvm.beginrescueend.com/install/rvm) Why not just: bash <(curl -s https://rvm.beginrescueend.com/install/rvm)

Chiara Coetzee Over a year ago

Small note: if wget is available but curl is not (e.g. on a stock Ubuntu desktop system), you can substitute wget -q http://mywebsite.com/myscript.txt -O - for curl -s http://mywebsite.com/myscript.txt).

Bruno Bronosky Over a year ago

Be aware that you can't pass command line arguments to your script. bash will_not_work foobar <(curl -s http://example.com/myscript.sh) If you own the script you can use environment variables instead like so: MYFLAG1=will_work bash MYFLAG2=foobar <(curl -s http://example.com/myscript.sh) and it also works with pipes like so: curl -s http://example.com/myscript.sh | MYFLAG1=will_work MYFLAG2=foobar bash This of course requires that you use MYFLAG1 and MYFLAG2 instead of $1 and $2

Yin Over a year ago

$ sudo bash <(curl -s xxx) got error: bash: /dev/fd/63: Bad file descriptor

Harsh Pandey Over a year ago

The first solution (the one using source) did not work at all. The second worked somewhat but has its limitations. It is executing the script from the URL in a subshell. I have some functions defined in the script that I would like to use in the parent. Is there anyway to achieve that? Or am I out of luck and the only solution is to copy that script in a temporary file and then source it?

|

Anandi Das · Accepted Answer · 2013-07-13 20:40:31Z

116

This is the way to execute remote script with passing to it some arguments (arg1 arg2):

curl -s http://server/path/script.sh | bash /dev/stdin arg1 arg2

answered Jul 13, 2013 at 20:40

Anandi Das

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1 Comment

Flores Robles Over a year ago

this breaks stty :\ use bash <(curl ... ) if you use stdin

user77115 · Accepted Answer · 2019-07-26 11:21:51Z

79

For bash, Bourne shell and fish:

curl -s http://server/path/script.sh | bash -s arg1 arg2

Flag "-s" makes shell read from stdin.

edited Jul 26, 2019 at 11:21

answered Mar 28, 2015 at 12:03

user77115

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3 Comments

hoijui Over a year ago

this should work in most shells, while the accepted answer does not work with fish, for example.

user9608133 Over a year ago

What is arg1 arg2?. Can I call just curl -s http://server/path/script.sh | bash -s?

user77115 Over a year ago

@Nairum Yes, you can call without arg1 and arg2, which are parameters passed to script.sh. If script.sh requires parameters to be able to execute, you can add as many parameters as you like. Having 2 parameters is just an example.

Bonifacio2 · Accepted Answer · 2018-08-30 19:33:15Z

23

Use:

curl -s -L URL_TO_SCRIPT_HERE | bash

For example:

curl -s -L http://bitly/10hA8iC | bash

edited Aug 30, 2018 at 19:33

Bonifacio2

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answered May 25, 2016 at 10:29

Katie MC

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Comments

Stephen Ostermiller · Accepted Answer · 2022-06-23 19:51:07Z

16

Using wget, which is usually part of default system installation:

bash <(wget -qO- http://mywebsite.example/myscript.txt)

edited Jun 23, 2022 at 19:51

Stephen Ostermiller♦

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answered May 16, 2013 at 9:48

amra

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1 Comment

amra Over a year ago

RTFM: gnu.org/software/wget/manual/wget.html. ||| -q == --quiet == "Turn off Wget’s output." ||| -O- == --output-document=- == If ‘-’ is used as file, documents will be printed to standard output.

Stephen Ostermiller · Accepted Answer · 2022-06-23 19:52:02Z

14

You can use curl and send it to bash like this:

bash <(curl -s http://mywebsite.example/myscript.txt)

edited Jun 23, 2022 at 19:52

Stephen Ostermiller♦

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answered Apr 20, 2011 at 19:42

Random832

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Comments

luismartingil · Accepted Answer · 2013-07-09 18:52:42Z

13

You can also do this:

wget -O - https://raw.github.com/luismartingil/commands/master/101_remote2local_wireshark.sh | bash

answered Jul 9, 2013 at 18:52

luismartingil

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Comments

Stephen Ostermiller · Accepted Answer · 2022-06-23 19:52:20Z

13

I often using the following is enough

curl -s http://mywebsite.example/myscript.txt | sh

But in a old system( kernel2.4 ), it encounter problems, and do the following can solve it, I tried many others, only the following works

curl -s http://mywebsite.example/myscript.txt -o a.sh && sh a.sh && rm -f a.sh

Examples

$ curl -s someurl | sh
Starting to insert crontab
sh: _name}.sh: command not found
sh: line 208: syntax error near unexpected token `then'
sh: line 208: ` -eq 0 ]]; then'
$

The problem may cause by network slow, or bash version too old that can't handle network slow gracefully

However, the following solves the problem

$ curl -s someurl -o a.sh && sh a.sh && rm -f a.sh
Starting to insert crontab
Insert crontab entry is ok.
Insert crontab is done.
okay
$

edited Jun 23, 2022 at 19:52

Stephen Ostermiller♦

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answered Jun 14, 2016 at 1:52

Chinglin Wen

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Comments

Vamsidhar Muggulla · Accepted Answer · 2016-09-20 09:24:44Z

12

The best way to do it is

curl http://domain/path/to/script.sh | bash -s arg1 arg2

which is a slight change of answer by @user77115

answered Sep 20, 2016 at 9:24

Vamsidhar Muggulla

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Comments

Thomas Decaux · Accepted Answer · 2015-02-13 13:54:37Z

8

Also:

curl -sL https://.... | sudo bash -

answered Feb 13, 2015 at 13:54

Thomas Decaux

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2 Comments

towry Over a year ago

What dose the last strip mean?

Mingjiang Shi Over a year ago

From the bash man page: A -- signals the end of options and disables further option processing. Any arguments after the -- are treated as filenames and arguments. An argument of - is equivalent to --.

ling · Accepted Answer · 2015-10-21 05:13:08Z

4

Just combining amra and user77115's answers:

wget -qO- https://raw.githubusercontent.com/lingtalfi/TheScientist/master/_bb_autoload/bbstart.sh | bash -s -- -v -v

It executes the bbstart.sh distant script passing it the -v -v options.

answered Oct 21, 2015 at 5:13

ling

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Comments

Mauricio Sánchez · Accepted Answer · 2018-07-25 21:23:21Z

2

Is some unattended scripts I use the following command:

sh -c "$(curl -fsSL <URL>)"

I recommend to avoid executing scripts directly from URLs. You should be sure the URL is safe and check the content of the script before executing, you can use a SHA256 checksum to validate the file before executing.

answered Jul 25, 2018 at 21:23

Mauricio Sánchez

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Comments

emrcftci · Accepted Answer · 2022-01-02 02:40:40Z

2

instead of executing the script directly, first download it and then execute

SOURCE='https://gist.githubusercontent.com/cci-emciftci/123123/raw/123123/sample.sh'

curl $SOURCE -o ./my_sample.sh
chmod +x my_sample.sh
./my_sample.sh

answered Jan 2, 2022 at 2:40

emrcftci

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Comments

javafoot · Accepted Answer · 2018-04-13 02:06:22Z

1

This way is good and conventional:

17:04:59@itqx|~
qx>source <(curl -Ls http://192.168.80.154/cent74/just4Test) Lord Jesus Loves YOU
Remote script test...
Param size: 4

---------
17:19:31@node7|/var/www/html/cent74
arch>cat just4Test
echo Remote script test...
echo Param size: $#

answered Apr 13, 2018 at 2:06

javafoot

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Comments

Stephen Ostermiller · Accepted Answer · 2022-06-23 19:52:43Z

1

If you want the script run using the current shell, regardless of what it is, use:

${SHELL:-sh} -c "$(wget -qO - http://mywebsite.example/myscript.txt)"

if you have wget, or:

${SHELL:-sh} -c "$(curl -Ls http://mywebsite.example/myscript.txt)"

if you have curl.

This command will still work if the script is interactive, i.e., it asks the user for input.

Note: OpenWRT has a wget clone but not curl, by default.

edited Jun 23, 2022 at 19:52

Stephen Ostermiller♦

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answered Dec 19, 2021 at 18:53

Ross Smith II

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Comments

Stephen Kennedy · Accepted Answer · 2018-12-15 22:34:49Z

-5

bash | curl http://your.url.here/script.txt

actual example:

juan@juan-MS-7808:~$ bash | curl https://raw.githubusercontent.com/JPHACKER2k18/markwe/master/testapp.sh


Oh, wow im alive


juan@juan-MS-7808:~$

edited Dec 15, 2018 at 22:34

Stephen Kennedy

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answered Dec 15, 2018 at 22:32

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1 Comment

korkman Over a year ago

This is straight up wrong. Test your scripts before posting and don't fake output.

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