How to write an if statement for the first line of a text file bash

[thomas130]

Hi guys me again
At the moment I got my md5sum checking working which I write to a text file and see below.


If the md5sum works it will write the output to check2.md5
test.txt: OK

If the md5sum fails it will write
test.txt: FAILED

How do I write if statement to check the output whether or not the md5sum failed or not ?

Thanks for any help in advance it would be useful if you could show me the syntax or just an a good example

Thanks
Tom


check1="/home/ops/Desktop/test1/check1.md5"
check2="/home/ops/Desktop/test1/check2.md5"

cd /home/ops/Desktop/test1
md5sum test.txt > $check1
cd /home/ops/Desktop/test3
md5sum -c $check1 > $check2

if [ dont know what to put here ]
then
echo "backup work"
else
echo "panic backup did'nt work"
fi

[hazel]

Every Linux command produces an "exit code" which is 0 for success or something else (usually 1) for failure. This is what you use to check whether it worked or not.

There are two main ways to do it. You can use the built-in shell variable $?, which stands for the exit code of the last command. Or you can use the command itself in certain syntactical structures, one of which happens to be the if...fi structure. So

if command;
 Do this;
else
 Do that;
fi

will check the exit code of command and use it as its governing condition.

You should be able to work out the rest for yourself.

[thomas130]

Every Linux command produces an "exit code" which is 0 for success or something else (usually 1) for failure. This is what you use to check whether it worked or not.

There are two main ways to do it. You can use the built-in shell variable $?, which stands for the exit code of the last command. Or you can use the command itself in certain syntactical structures, one of which happens to be the if...fi structure. So

if command;
 Do this;
else
 Do that;
fi

will check the exit code of command and use it as its governing condition.

You should be able to work out the rest for yourself.

I have now amended my script and is now working the way I wanted it to do.

Thank you very much for your help

#!/bin/bash

check1="/home/ops/Desktop/test1/check1.md5"
#check2="/home/ops/Desktop/test1/check2.md5"


cd /home/ops/Desktop/test1
md5sum test.txt > /home/ops/Desktop/test1/check1.md5
cd /home/ops/Desktop/test3
md5sum -c /home/ops/Desktop/test1/check1.md5

if [ $? -eq 0 ];
then
echo "backup work"
else
echo "panic backup did'nt work"
fi