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Following script statement for user input is nested in while loop under if block but it doesn't work and is being skipped. How do I get user input to work?

exec 3<&0 && read -p 'Enter your answer: ' uservar <&3

FILE="hostnames.txt"
echo $(sudo chmod +777 $FILE)
echo "Step 1. Checking if file with hostnames exists."

#exec 3<&0

if [ -f "$FILE" ]
then
  echo "PASSED: File hostnames.txt does exist." && echo ""
  while IFS= read -r hostname;
    do
     echo "Step 2. Checking Grph mgmt_con_ip4 exists for $hostname"
     mgmt_con_ip4="$(echo "$(llama-grph node show $hostname | grep mgmt_con_i$
     echo "Grph has management IPv4 address: $mgmt_con_ip4"
     if [ -z $mgmt_con_ip4 ]
       then
         echo "PASSED: Grph mgmt_con_ip4 == NULL" && echo ""
       else
         echo "FAILED: Grph mgmt_con_ip4 == NOT NULL" && echo ""
         echo "$(ipam --format json get-cidr-parent $mgmt_con_ip4)" && echo ""
         echo "WARNING: OOB networks shouldn't have $mgmt_con_ip4 IPv4 addres$
         exec 3<&0 && read -p 'Enter your answer: ' uservar <&3
     fi
  done < $FILE
fi
Python_new
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  • why? your user input question seem like it should be done **outside** of the while loop - you don't want it to ask for every line of $FILE, do you? It doesn't even seem to be asking a question, anyway - just stating "FAILED" and "WARNING" and then prompts the user for an answer - an answer to what? there's no question there. – cas Mar 31 '23 at 01:32
  • Other comments: 1. using `sudo chmod 777` to brute-force RWX permissions is a bad idea. If the user running the script should have permission then it should be set up that way in the first place. 2. [quote your variables](https://unix.stackexchange.com/q/131766) - e.g. `[ -z $mgmt_con_ip4 ]` will be a syntax error if `mgmt_con_ip4` is empty because it will expand to just `[ -z ]`. use `[ -z "$mgmt_con_ip4" ]` instead. See also [$VAR vs ${VAR} and to quote or not to quote](https://unix.stackexchange.com/q/4899) – cas Mar 31 '23 at 01:35
  • @cas Note: `[ -z ]` is not a syntax error. It should be equivalent to `[ -n -z ]` and this is true, like `[ -z "$mgmt_con_ip4" ]` is when `$mgmt_con_ip4` expands to an empty string. So `[ -z $mgmt_con_ip4 ]` "would work" in case of an empty string; it's still bad code, but the result is as expected. Errors will happen if unquoted `$mgmt_con_ip4` expands to multiple words. – Kamil Maciorowski Mar 31 '23 at 05:20
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    @KamilMaciorowski that's true, i forgot that's how single args are handled by `[` / `test`. the real problem with `-z` here is, as you say, word splitting of an unquoted var. also worth noting: the test would produce an incorrect result if `-n` were used instead of `-z`. – cas Mar 31 '23 at 05:32
  • Aside from the other problems mentioned, the one in the title is due to stdin (FD #0) being redirected from `$FILE` inside the loop, and copying it to FD #3 doesn't change that. Solution: read the file via FD #3 and leave stdin alone. Something like `while IFS= read -r hostname <&3; ... done 3< "$FILE"`. See my answer to [this previous question](https://unix.stackexchange.com/questions/139652/user-input-not-accepted-in-nested-case-statement/139653#139653). – Gordon Davisson Mar 31 '23 at 20:23

0 Answers0