Issues while create a file in shell scripting in jenkins pipeline script - shell

Question

I am trying to create a multi line file in Jenkins pipeline script using the below commands.
sh "echo \"line 1\" >> greetings.txt"
sh "echo \"line 2\" >> greetings.txt"
echo "The contents of the file are"
sh 'cat greetings.text'
sh 'rm -rf greetings.txt'
Unforunately , I am not able to create the file named greetings.txt. Can any one please let me know, where I am going wrong.
Results in Jenkins console:
[tagging] Running shell script
+ echo 'line 1'
[Pipeline] sh
[tagging] Running shell script
+ echo 'line 2'
[Pipeline] echo
The contents of the file are
[Pipeline] sh
[tagging] Running shell script
+ cat greetings.text
cat: greetings.text: No such file or directory
Any suggestions would be helpful.
Thanks!

Answer 1

This can be solve this by using single quotes with sh, so you don't need to use escaping. Also you have to create an initial file with > and add content with >>:
pipeline{
agent any
stages{
stage('write file'){
steps{
sh 'echo "line 1" > greetings.txt'
sh 'echo "line 2" >> greetings.txt'
echo "The contents of the file is"
sh 'cat greetings.txt'
sh 'rm -rf greetings.txt'
}
}
}
}
output:
[test] Running shell script
+ echo line 1
[Pipeline] sh
[test] Running shell script
+ echo line 2
[Pipeline] echo
The contents of the file is
[Pipeline] sh
[test] Running shell script
+ cat greetings.txt
line 1
line 2
[Pipeline] sh
[test] Running shell script
+ rm -rf greetings.txt
[Pipeline] }
[Pipeline] // stage
[Pipeline] }
[Pipeline] // node
[Pipeline] End of Pipeline
Finished: SUCCESS

Answer 2

It's not finding a file named greetings.text because you didn't create one (a litte typo in the extension in your cat line). Try sh 'cat greetings.txt', or even better adjusted your script:
sh "echo \"line 1\" >> greetings.txt"
sh "echo \"line 2\" >> greetings.txt"
echo "The contents of the file are"
sh 'cat greetings.txt'
sh 'rm -rf greetings.txt'
If you want to use multiline commands, you can also use this syntax:
sh """
echo \"line 1\" >> greetings.txt
echo \"line 2\" >> greetings.txt
echo "The contents of the file are:"
cat greetings.txt
rm -rf greetings.txt
"""
From the last example, this should generate an output like:
Running shell script
+ echo 'line 1'
+ echo 'line 2'
+ echo 'The contents of the file are:'
The contents of the file are:
+ cat greetings.txt
line 1
line 2
+ rm -rf greetings.txt