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I have a simple shell script I copied from a working script. It works if I copy-paste it to a terminal:

if true
then
  true
fi

However, when I run the script with bash myscript, I get various syntax errors as if some of the keywords are missing.

  • myscript: line 4: syntax error near unexpected token `fi' , as if then isn't there.
  • myscript: line 6: syntax error: unexpected end of file , as if fi isn't there.
  • myscript: line 4: syntax error near unexpected token `$'\r' .. what?

Why does this happen in this particular script, but not on my command line or in the script I copied from?

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7
  • 1
    Consider adding shellcheck.net to your automated testing workflow. Commented Aug 7, 2015 at 20:31
  • Is there a Windows machine in the vicinity of the code? Could there be carriage returns in the non-working version? One of the errors uses $'\r' which suggests this is the problem. See How to convert DOS/Windows newline (CRLF) to Unix newline (\n) in bash script? amongst many other relevant questions. Commented Aug 7, 2015 at 20:32
  • @JonathanLeffler Yes, I fabricated this question and gave a community answer because I'm never able to find a general question for marking as duplicate. For example, the one you suggest is about how to convert a file and it would not be obvious to a poster why that's at all relevant. I've added this one to the bash tag wiki, but if you find a better one I'm happy to switch it. Commented Aug 7, 2015 at 20:36
  • It's been asked so many times that it is surprising that you failed to find useful information. Here are a couple 1, 2 Commented Aug 8, 2015 at 11:30
  • @ThomasDickey If you update the bash tag wiki with any question you'd think make a better, general, canonical FAQ for deduping syntax errors due to CR, I'll be absolutely delighted to delete this question! (Finding good ones are tricky, as evidenced by your #2 being this very post.) Commented Aug 8, 2015 at 16:57

1 Answer 1

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19

TL;DR: Your script has Windows style CRLF line endings, aka \r\n.

Convert to Unix style \n by deleting the carriage returns.

How do I check if my script has carriage returns?

They're detectable as ^M in the output of cat -v yourscript:

$ cat -v myscript
if true^M
then^M
  true^M
...

How do I remove them?

Set your editor to save the file with Unix line endings, aka "line terminators" or "end-of-line characters", and resave it.

You can also remove them from a command line with dos2unix yourscript or cat yourscript | tr -d '\r' > fixedscript.

Why do carriage returns cause syntax errors?

The carriage return character is just another character to bash. then is not the same as then\r, so bash doesn't recognize it as a keyword and assumes it's a command. It then keeps looking for a then and fails

If there happens to be a trailing space after then, you get a similar problem for fi.

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