BASH syntax error: unexpected end of file

I have the following little bash script attempting to tell me if my ISP has altered my IP address.

#!/bin/bash
getip=" ";
$getip=$(/usr/bin/dig +short myip.opendns.com @resolver1.opendns.com);
if [[ $getip==" " ]]; then
    echo "Currently offline but ip address is $gotip" > /media/ramdisk/message.txt;
else
if [[ "$getip" != "$gotip" ]]; then
    gotip=$(cat /home/alf/gotip.txt);
    echo "ip address was $gotip is now $getip" > /media/ramdisk/message.txt;
    echo $getip > /home/alf/gotip.txt;
fi
/usr/bin/mail -s "IpChanged for $(uname -n)" alf@stockton.co.za < /media/ramdisk/message.txt;
exit 1

when I run it I get :-

/home/alf/Develop/bash/IpChanged.sh: line 3: =41.145.54.222: command not found
/home/alf/Develop/bash/IpChanged.sh: line 14: syntax error: unexpected end of file

Please tell me what I have done wrong.

What are you trying to do with this? Its not correct.

getip=" ";
$getip=$(/usr/bin/dig +short myip.opendns.com @resolver1.opendns.com);

use shellcheck to check your script. It will tell you what you have done wrong.

You should fix line #3 first.

Many times an error at the end of a script it's because it's missing a newline. Not sure if that's a technical thing, just something I run into sometimes. But fix line #3 first.

You can test line #3 on the command line to get it correct also.

Originally Posted by stockton if [[ $getip==" " ]]; then echo "Currently offline but ip address is $gotip" > /media/ramdisk/message.txt; else if [[ "$getip" != "$gotip" ]]; then

These are two separate "if"s, so you'll need two "fi"s to terminate them.

If you replace the "else
if"
construction with a single "elif" you would need only one, but now it is a separate "if" within the "else" part of the first if, so the first "fi" will terminate this 2nd "if" (only) and somewhere (beyond that first fi) there must be another fi to terminate that else block.

could you use process of elimination in your if statements with the data and scenario that is being used?

if it is not one condition then it has to be the other one logic.

where only two conditions can be had.

if [[ 'a' != 'b' ]] ; then 
     #not equal
else # it will be equal so no more checking needed
    #just run the code on the data, or operations needed to be ran
fi

or as pointed out, if it is an unknown or more that two conditions can be had then check for them that you are looking for within the total amount of conditions that are possible.

using process of elimination logical thinking.

if [[ something == one thing ]] ; then
       do something if condition matches.
elif [[ something == the other thing ]] ; then 
     do something if the condition matches this instead. 
fi

where that type of structure can have more then one elif to cover all of the possibilities one can think of, all the way down to what it can only be left with using process of elimination.

if more than two conditions can be had, then it is written as such

if [[ true ]] ; then
  do something
elif [[ true ]] ; then 
  do something
elif [[ true ]] ; then 
  do something
else
  do something on the only possibility left
  that the condition the data could be in
fi

if this can be had, then rethinking your code, would using a case ( switch ) statement be a better choice in replacement of the if elif else structure.

the switch statement in other programming languages, in BASH it is called a case statement, and they are faster in execution.

the if conditional can also be compounded as this is what you might have been trying to do.

if [ true ] ; then 
   if [ true ] ; then
       do something
   fi
else
 do something
fi

one more

if [ true ] ; then 
   if [ true ] ; then
     do something 
   fi
elif [ true ] ; then
 if [ true ] ; then
   do something
  fi
else
  do something
fi

as you can see they can get rather complex. Also a switch or case statement. Can it be used in place of that complexity to ease the understanding of the code and speed up its execution as well?

Didn't notice the if/else issue. I fully agree, that's something which you'll run into once you fix the earlier problem.

Take a look at line #2 where you properly and successfully assign something to the variable getip. Note the correct syntax you used.

Now take a look at line #3 where you go to re-assign that variable. You've chosen an incorrect syntax.

For all that, you do not need to initialize getip before you assign it. Just assign it using the dig command you have coded.

Later in the script you introduce the variable gotip. Where did it come from?

to ping in again, why is your script always sending an exit 1 code for failure? I'd write it like this then check to be sure it worked. If not, adjust it accordingly.

#!/bin/bash

## assign a variable for a path for ease of changing it in only one
#location if needed to be changed
pathto=~/
#same for file name
messagefile="message.txt"

#was not declared nor assigned a value
gotip="???????"

#does not need to be declared then set to null
#getip=" ";

#removed $ because you are not referencing it but assigning it a value
#the varitbale that is
getip=$(/usr/bin/dig +short myip.opendns.com @resolver1.opendns.com);


#if variable is null or empty
#can be written either like this
#if [[ ! -n "$getip" ]] ; then
#or like this

if [[ -z "$getip" ]]; then
    echo "Currently offline but ip address is $gotip" > $pathto/$messagefile;
    #exit 1 #maybe here because it failed to send a message???
elif [[ "$getip" != "$gotip" ]]; then

	#change this 
    #gotip=$(cat /home/alf/gotip.txt);
    #to this perhaps
    
    
    gotip=$(cat $HOME/gotip.txt);
    echo "ip address was $gotip is now $getip" > $pathto/$messagefile;
    echo $getip > $HOME/gotip.txt;
    #exit 0 here because it sent a message? 
fi

/usr/bin/mail -s "IpChanged for $(uname -n)" alf@stockton.co.za < $pathto/$messagefile;
#check return code of mail, can be used to send  ( user / coder (re)assigned ) error number 
#or error number gotten from mail (return code)
[[ $? -eq '0' ]] && echo "success! exit = $?" || echo "Failed to send message exit = $?" 


#exit 1
#change to success??
#exit 0

https://linux.die.net/man/1/mail

Originally Posted by BW-userx as you can see they can get rather complex. Also a switch or case statement.

Correct indentation, as you rightly did, helps a lot in showing the blocks in compound statements like if .. then .. else .. fi, case .. in .. esac, while .. do .. od (etc.)
If the 2nd if would have been indented the Op would more easily seen that there's a fi missing.
I worked the other way 'round, as the error msg was "unexpected end of file" I was looking for something that wasn't terminated correctly.

Originally Posted by ehartman Correct indentation, as you rightly did, helps a lot in showing the blocks in compound statements like if .. then .. else .. fi, case .. in .. esac, while .. do .. od (etc.) If the 2nd if would have been indented the Op would more easily seen that there's a fi missing. I worked the other way 'round, as the error msg was "unexpected end of file" I was looking for something that wasn't terminated correctly.

I immediately went to look for that missing quote that often gives that error. then seen what you found, that if else, thing, so I thought I'd just explain it a little further.