Bash: evaluating $? variable (if statement)

Shell Programming and Scripting
1

Hello, i'm unable to write a correct if... statement to evaluate the $? variable.

Could anybody send to me an example? for example, this lines of code didn't work...

if [ $? eq 0 ]; then
etc etc

if [ $? == 0 ]; then
etc etc

Thank you in advanced.

2

This code works fine for me.

if [ $? == 0 ]
then 
echo "hello"
else
echo "goobye"
fi
3

I'm using bash

#!/bin/bash
echo "Parameter $1"
echo "$?"
$SCHRODINGER/utilities/reagentprep -listfull | grep $1
echo "$?"

if [ $? == 1 ]then
echo "Error"
exit
fi

echo "OK"
exit

The output is always the same, with an incorrect (AAA) and an correct (Thiol_S_H) $1 parameter

Parameter AAA
0
Checkout succeeded: MMLIBS/0722 6816 F1B7 A2A5
License file: /opt/schrodinger/license
License Server: xxx@yyy.es
1
OK

and

Parameter Thiol_S_H
0
Checkout succeeded: MMLIBS/0722 6816 F1B7 A2A5
License file: /opt/schrodinger/license
License Server: xxx@yyy.es
23 Aryl_or_Vinyl_Thiol_S_H
38 Thiol_S_H
0
OK

Thankxxx!!!

4

And this is why we want to see the code

#!/bin/bash
echo "Parameter $1"
echo "$?"
$SCHRODINGER/utilities/reagentprep -listfull | grep $1
echo "$?"

if [ $? == 1 ]then
echo "Error"
exit
fi

the if statement is evaluating the echo Condition, not the grep as intended.

try instead

$SCHRODINGER/utilities/reagentprep -listfull | grep $1

STATUS=$?
echo "$STATUS"

if [ $STATUS == 1 ]then
echo "Error"
exit
fi
5

Are you giving proper space after and before the brackets like this

if [ $? == 0 ];
 then
    echo "hello"
fi
6

Shame on me... thank you very much!!!