如果 grep 有结果，请发送 email

Question

I'm trying to do a simple script that if the "grep" comes with results, send the email with the results. But I want also to send an email if there is a case when there are no rejects

#! /bin/bash

FILE=$(find . /opt/FIXLOGS/l51prdsrv* -iname "TRADX_*.log" -type f -exec grep -F 103=16 {} /dev/null \; )>> Rejects.txt

if [ "$FILE" == true ]
then
    mailx -s "Logs $(date +%d-%m-%y)" "email" < Rejects.txt
    rm -f Rejects.txt
elif [ "$FILE" == null ]
then 
    echo "No Rejects" >> Rejects.txt
    mailx -s "Logs $(date +%d-%m-%y)" "email" < Rejects.txt
    rm -f Rejects.txt
fi

Answer 1

In bash, everything is pretty much just a string. null is a string, not a null reference like in other languages. true is also a string (unless it's the command true , but that's not the case in your comparison).

If you want to test that a file exists, you'd use [[ -f "$FILE" ]] . However, the file is going to exist in your case even if grep matches nothing because bash automatically creates the file when you set it as the destination for your output. What you really need is -s which tests if the file exists and has size greater than 0.

#!/bin/bash
find . /opt/FIXLOGS/l51prdsrv* -iname "TRADX_*.log" -type f -exec grep -F 103=16 {} /dev/null \; >> Rejects.txt

if [[ -s Rejects.txt ]] ; then
 : # grep wrote stuff into the file
else
 : # file is empty so grep found nothing
fi