I have an issue with this Below Code
getting an error called :
[: -!eq: binary operator expected]
How do I fix this error
RC=$?
if [ $RC -eq 0 ]; then
echo File: $j Deletion Successfull >> $_Main/Status"_"$_date
else
echo File: $j Deletion Failed >> $_Main/Status"_"$_date
fi
The source of the error: [: –le: binary operator expected might be that you are using the unicode version of "–" instead of the regular "-".
Check your keyboard settings / mappings and try to use the normal "-".
You code is running perfectly well. However, if i change it like that :
#!/bin/sh
RC=$?
if [ $RC eq 0 ]; then
echo File:
else
echo File:
fi
I got the same error :
./test.sh: line 4: [: eq: binary operator expected
File:
This means you should check that you are using -eq and not anything else. The problem is clearly located into your condition.
In your case, seems that you tried to negate the equals condition with a !. This clearly won't work.
Related
To satisfy function requirements I have to retrieve a parameter which is a duty cycle (0-100% in 0.01%).
For test, I wrote something simple like :
#!/bin/bash
#
if [ "$1" -lt 0 ] || [ "$1" -gt 100 ]
then
echo "bad param"
else
echo "ok"
fi
I obtain :
root#:~# ./test.sh 11
ok
root#:~# ./test.sh 11,01
./test.sh: line 4: [: 11,01: integer expression expected
./test.sh: line 4: [: 11,01: integer expression expected
bad param
How to realise this kind of test ?
bash can only operate in integer arithmetics. If you need floats, use an external tool like bc:
if (( $( bc <<< "($1 < 0) || ($1 > 100) " ) )) ; then
...
fi
I would rather switch to a more powerful language for the whole script, though (like Perl)/
I'm trying to read from user and then do the following.
read framechoice
if [ $framechoice -gt 100 ]; then
if [ $framechoice -lt 0 ]; then
framechoice=101
fi
fi
It gives me the following error.
[: -gt: unary operator expected
Can anyone tell me where I am going wrong.
This happens if you don't input anything:
$ cat myscript
read framechoice
if [ $framechoice -gt 100 ]; then
if [ $framechoice -lt 0 ]; then
framechoice=101
fi
fi
$ bash myscript
<enter>
myscript: line 2: [: -gt: unary operator expected
Try instead to actually enter something:
$ bash myscript
42<enter>
The script then exits with success.
Your program needs to cope with empty input. This is most easily achieved by properly quoting the variable; then
if [ "$framechoice" -gt 100 ]; then
evaluates to [ "" -gt 100 ] which is no longer is a syntax error; however, instead, it throws the warning integer expression expected.
Even better, maybe filter the input so that you do not attempt numeric comparisons before making sure the input is numeric.
Okay, so within my script (this is my first time working with Bash) I am being met with two unary operator expected errors. The code itself is actually working fine, but it's presenting me with these errors at runtime:
[: !=: unary operator expected
For the line:
if [ ${netmask[1]} != "" ]; do
So for the first error, it's thrown when ${netmask[1]} is "" (null). I have tried multiple ideas and still can't get it to work without returning that error in the process.
I solved it by adding quotation marks (grrr)
if [ "${netmask[1]}" != "" ]; do
If you want to check for the null value for a variable, use the -z operator:
if [ -z "${netmask[1]}" ]; then
On example:
VAR=""
if [ -z "$VAR" ]; then
echo This will get printed
fi
Please note the parentheses around the variable: "$VAR".
I would like to define a prompt which will indicate with colors whether the command executed properly and whether the command was found. As for now I have something like this but I does not work properly.
PS1="\`COMMAND_RESULT=\$\?;
if [ $COMMAND_RESULT -eq 127 ]; then echo \[\e[33m\] ---=== Command not found ===--- ;
elif [ $COMMAND_RESULT -ne 0 ]; then echo \[\e[33m\]---=== \[\e[31m\]Oh noes, bad command \[\e[33m\]==---;
fi\`
\n\[\e[0;37m\][\[\e[1;31m\]\#\[\e[0;37m\]]
\[\e[0;32m\]\u\[\033[1;33m\]#\[\033[0;32m\]\h
As for now I get this error on bash start :
-bash: [: -eq: unary operator expected
-bash: [: -ne: unary operator expected
Don't pollute your PS1 with functions. You should use the special PROMPT_COMMAND variable to do this. The value of PROMPT_COMMAND is executed as a command prior to issuing each primary prompt.
Here is an example:
_check_command(){
local COMMAND_RESULT=$?
if [ $COMMAND_RESULT -eq 127 ]
then
echo -e "\e[1;33m---=== Command not found ===---\e[m"
elif [ $COMMAND_RESULT -ne 0 ]
then
echo -e "\e[1;31m---=== Oh noes, bad command ===---\e[m"
fi
}
PROMPT_COMMAND='_check_command'
PS1="\[\e[0;37m\][\[\e[1;31m\]\#\[\e[0;37m\]] \[\e[0;32m\]\u\[\033[1;33m\]#\[\033[0;32m\]\h "
There are many bash prompts you can find online to guide you. Here is one good example.
You probably should not escape $? as \$\?. Looks like it gets interpreted literally.
Also you can check out the Arch Wiki article that shows how to implement something similar to what you want. Look at this line:
PS1="$(if [[ ${EUID} == 0 ]]; then echo '\[\033[01;31m\]\h'; else echo '\[\033[01;32m\]\u#\h'; fi)\[\033[01;34m\] \w \$([[ \$? != 0 ]] && echo \"\[\033[01;31m\]:(\[\033[01;34m\] \")\$\[\033[00m\] "
especially this part:
([[ \$? != 0 ]] && echo \"\[\033[01;31m\]:(\[\033[01;34m\] \")
while [ $done = 0 ]
do
echo -n "Would you like to create one? [y/n]: "
read answer
if [ "$(answer)" == "y" ] || [ "$(answer)" == "Y" ]; then
mkdir ./fsm_$newVersion/trace
echo "Created trace folder in build $newVersion"
$done=1
elif [ "$(answer)" == "n" ] || [ "$(answer)" == "N" ]; then
$done=2
else
echo "Not a valid answer"
fi
done
Ok so I have this simple bashscript above that simply just tries to get input from a user and validate it. However I keep getting this error
./test.sh: line 1: answer: command not found
./test.sh: line 1: answer: command not found
./test.sh: line 1: answer: command not found
./test.sh: line 1: answer: command not found
Which I have no idea why because "answer" is nowhere near line 1. So I ran into this article
Which makes sense since it's referring to line 1 and can't find answer. So it seems to be starting a new subshell. However I didn't really understand the solution and can't see how I would apply it to my case. I just wanna get this to work.
$(answer) doesn't substitute the value of the variable answer. It executes answer as a command, and substitutes the output of that command. You want ${answer} everywhere you have $(answer). In this case you can get away with bare $answer too, but overuse of ${...} is good paranoia.
(Are you perhaps used to writing Makefiles? $(...) and ${...} are the same in Makefiles, but the shell is different.)
By the way, you have some other bugs:
In shell, you do not put a dollar sign on the variable name on the left hand side of an assignment. You need to change $done=1 to just done=1 and similarly for $done=2.
You are not being paranoid enough about your variable substitutions. Unless you know for a fact that it does the wrong thing in some specific case, you should always wrap all variable substitutions in double quotes. This affects both the mkdir command and the condition on the while loop.
You are not being paranoid enough about arguments to test (aka [). You need to prefix both sides of an equality test with x so that they cannot be misinterpreted as switches.
== is not portable shell, use = instead (there is no difference in bash, but many non-bash shells do not support == at all).
Put it all together and this is what your script should look like:
while [ "x${done}" = x0 ]; do
echo -n "Would you like to create one? [y/n]: "
read answer
if [ "x${answer}" = xy ] || [ "x${answer}" = xY ]; then
mkdir "./fsm_${newVersion}/trace"
echo "Created trace folder in build $newVersion"
done=1
elif [ "x${answer}" = xn ] || [ "x${answer}" = xN ]; then
done=2
else
echo "Not a valid answer"
fi
done
Which I have no idea why because
"answer" is nowhere near line 1. So I
ran into this article
That's not your problem here.
I ran the script and did not get the error you got. I did receive the error:
./test.sh: line 1: [: -eq: unary operator expected
when I tried to compile though. Defining done fixed this. The following script should work...
#!/bin/bash
done=0
while [ $done -eq 0 ]
do
echo -n "Would you like to create one? [y/n]: "
read answer
if [[ "$(answer)" == "y" || "$(answer)" == "Y" ]]; then
mkdir ./fsm_${newVersion}/trace
echo "Created trace folder in build $newVersion"
$done=1
elif [[ "$(answer)" == "n" || "$(answer)" == "N" ]]; then
$done=2
else
echo "Not a valid answer"
fi
done
...note you were doing string comparisons on your done variable, which you apparently intended to be numeric. It's generally bad form to do string comparison on a numeric type variable, though it will work. Use -eq (arithmetic comparison operator) instead. (Also note that if you kept that test, your string equality would be inconsistent... you had "=" in one spot and "==" in another spot... nitpicking here, but it's helpful to be consistent).
Also, I suggest double brackets for your compound conditionals as they will be more readable if you have longer ones. e.g.
if [[($var1 -eq 0 && $var2 -eq 1) || ($var1 -eq 1 && $var2 -eq 0)]]; then
Just a matter of preference as you only have two conditions, but could be useful in the future.
Also you were missing braces '{' '}' around your newVersion variable.
Finally, I'd suggest putting the line #!/bin/bash on the top of your script. Otherwise its up to your environment to determine what to do with your script, which is a bad idea.