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I have this:

bash <(
  curl_url='https://raw.githubusercontent.com/oresoftware/run-tsc-if/master/run.sh'
  curl -H 'Cache-Control: no-cache' --silent "$curl_url"
)

the bash script at that url, takes one argument $1...is there a way to pass an argument using this style of execution or would I need to use an environment variable instead?

I supposed this could work?

bash "first arg" <(
  curl_url='https://raw.githubusercontent.com/oresoftware/run-tsc-if/master/run.sh'
  curl -H 'Cache-Control: no-cache' --silent "$curl_url"
)

but that's just a guess, and seems wrong..

ok from my testing this does seem right:

bash  <(
  my_url='https://raw.githubusercontent.com/oresoftware/run-tsc-if/master/run.sh'
  curl -H 'Cache-Control: no-cache' --silent "$my_url"
) "first arg"  # add the argument here

if someone could verify that'd be good..it seems like this verifies it:

bash <(echo 'echo "first: $1"') 'blaq'

that will echo:

first: blaq

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3
  • 1
    Why the downvotes? This looks like a reasonable way to avoid storing a run-once script locally. Commented Sep 6, 2019 at 12:09
  • you can verify yourself by using set -x in your shell, and see what a process substitution like <(...) turn into, and why the last version works. Commented Sep 6, 2019 at 12:51
  • @l0b0 the OP doesn't need to have bash read the downloaded script from its stdin (bash reading a script from stdin in bash is horrible, because it will do a read(2) system call for each byte, and may have other inintended consequences). Simply bash <(curl ...) av1 av2 av3 ... would work. (Of course, running scripts off githup is madness, but that's not a technical problem ;-)). Commented Sep 6, 2019 at 12:56

2 Answers 2

Reset to default
2

You can use a process substitution and redirect the resulting script to Bash's standard input:

$ bash -s 'first argument' 'second argument' < <(echo 'printf "%s\n" "$@"')
first argument
second argument

Replace the echo command with curl and you're good.

From man bash:

If the -s option is present, or if no arguments remain after option processing, then commands are read from the standard input. This option allows the positional parameters to be set when invoking an interactive shell.

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2
  • not sure if it's necessary, this works: bash <(echo 'echo "first: $1"') 'blaq' Commented Sep 6, 2019 at 16:44
  • see my answer, maybe you can answer the sub-question in my answer thx Commented Sep 6, 2019 at 16:46
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These both seem to work:

bash <(echo 'echo "first: $1 second: $2"') '111' '222'

and

bash -s '111' '222' < <(echo 'echo "first: $1 second: $2"')

looks like the first one, bash is reading from the file descriptor from the first argument, in the second one, it's reading from stdin.

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