Github Action: Split Long Command into Multiple Lines
1. Github Action: Split Long Command into Multiple Lines
I have a Github action command that is really long:
name: build
on: [push]
jobs:
build:
runs-on: ubuntu-18.04
steps:
- uses: actions/checkout@v1
- name: Install Prerequisites
run: |
sudo apt-get update
sudo apt-get install -y --no-install-recommends "a very very long list of prerequisites"
May I know whether it is possible to split the long command into multiple lines for better readability? I have tried the separator ’\’ but it does not work. Thanks in advance.
Comments
1.1. Answer 1
I have a multi line command using backslash to separate the lines as follows:
- name: Configure functions
run: |
firebase functions:config:set \
some.key1="${{ secrets.SOME_KEY_1 }}" \
some.key2="${{ secrets.SOME_KEY_2 }}" \
...
Note the preceding ’|’ character.
Comments:
- (tom) This is the correct answer and would be a better accepted answer. The backslashes work the same as a multiline command in bash. (I’d recommend a hanging indent for readability though.)
- (dan1st) Does anyone know since when this is possible? (I think it was not possible when I wrote my answer but I fully agree with that answer being accepted, now)
- (Bojian Zheng) @dan1st I also do not think this is possible by the time I asked this, but it seems that Github people have added the support for backslash.
- (mcserep) I don’t know how did it work previously for anyone, but adding a backslash does not work right now with GitHub Actions. This shouldn’t be the accepted answer.
- (IvanD) I confirm: this does not work on GitHub Actions as of now. You need to use “>” instead of “I” (see other answers)
1.2. Answer 2
You can use the YAML folded style with > which is supported by GitHub Actions.
For example,
run: > xvfb-run ./mvnw -f my/pom.xml clean verify -DskipTests
newlines will be replaced with spaces so the above is equivalent to
run: xvfb-run ./mvnw -f my/pom.xml clean verify -DskipTests
Comments:
- (sschuberth) Also see yaml-multiline.info to play around with the different scalar / chomping styles.
- (Johnny Oshika) This works, thank you! Important note: per yml spec, white space is important here, so any extra tabs before the lines will cause problems.
- (OZZIE) It seems to work but it doesn’t fail on any errors, same with | also.. so it becomes kind of pointless..
- (ruohola) @JohnnyOshika Thank you for that comment! It cleared a long standing misunderstanding for me.
- (Waldir Leoncio) Just a quick note about this being for the default shell. For example, my YML file had some bits running R code with shell: Rscript {0}, and line breaking in those cases don’t need any special characters (just like in R).
1.3. Answer 3
Going to share this in since it has not been mentioned. You can use: I found the site yaml-multiline.info useful for understanding how yaml strings are interpreted. For my use case, I ended up doing the following:
run: >-
for i in $(find . -type f -name "*.log");
do
echo "File: ${i} \n";
cat $i;
printf '%*s\n' "${COLUMNS:-$(tput cols)}" '' | tr ' ' -;
done
Comments:
- (silkfire) What does the hyphen in >- do?
- (Arclite) @silkfire According to the linked website, it appears to strip newlines from the end of the block, so that there’s not an extra trailing \n at the end.
- (Arclite) That said, this is not supported by GitHub Actions: github.com/actions/runner/issues/418
1.4. Answer 4
This was not possible using backslashes, earlier. See the accepted answer on how to do it now. As far as I know, GitHub Actions does not support that. However, you can use environment variables for that. For example, this script splits your command in 3 lines of code and executes it as one line.
steps:
- name: Install Prerequisites
run: |
sudo apt-get update
bash -c "$line1 $line2 $line3"
env:
- line1='sudo apt-get install -y --no-install-recommends '
- line2='a very very long list'
- line3='of prerequisites'
It creates the environment variables line1, line2 and line3 and concats and executes them in a bash session.
Comments: