I am writing an If then else script to check if a certain value exists in a file. If the value exists, print value exists, else print value does not exist.

#This script will check a file and determine if the QID exists.
#search the zero day file for qids and system tracking id's. These are contained in
#the file file.

echo What is the QID number $HOME?
read QID

#Set some variables
Qualyfile=$(cat /home/dc368/zeroday/zerodayresearch)

If [ $Qualyfile|grep $QualysID = $QualysID ]; then 
    echo qid exists
else echo qid does not exist
  • Hey ItGuru1, what is the question? Let us know, then we can help you. – Joe M Sep 24 '18 at 16:52
  • 1
    Paste your code into shellcheck.net for bash syntax errors – glenn jackman Sep 24 '18 at 17:05
  • My script keeps failing at this line: "If [ $Qualyfile|grep $QualysID = $QualysID ]; then ". Not sure what I need to do to fix. All I am trying to do is search a file for a certain number. If that number is there, print some message. If that number is not there, print some other message. Here is the error in debug mode: ------------------------------- ./zero.research: line 14: syntax error near unexpected token then' ./zero.research: line 14: If [ $Qualyfile|grep $QualysID = $QualysID ]; then ' – ITguru1 Sep 24 '18 at 17:14

Note that, after if, you put a command. Depending on the exit status of that command, you enter the then block or the else block. Also note that [ is a command, not just syntax (at a bash prompt, type help [ then help test)

You want

read -p "What is the QID? " qid
if grep -q "$qid" "$file"; then
    echo qid exists
    echo qid does not exist

Since grep uses regular expressions, this may return false positives. For example, if qid=., grep returns "true" if there is at least one character in the file. Read man grep for the extensive options to help narrow your results (hint, consider the -w and -F options.

Note also that I have avoided using ALLCAPS variable names. They can cause problems if you're not careful. Best practice is to avoid using them.

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