I'm getting started with bash scripting and made this little script following along a short guide but for some reason when I run the script with sh myscript I get
myscript: 5: myscript: 0: not found running on ubuntu 12.04
here is my script below I should at least see the echo message if no args are set:
#!/bin/bash
#will do something
name=$1
username=$2
if (( $# == 0 ))
then
echo "##############################"
echo "myscript [arg1] [arg2]"
echo "arg1 is your name"
echo "and arg2 is your username"
fi
var1="Your name is ${name} and your username is ${username}"
`echo ${var1} > yourname.txt`
`echo ${var1} > yourname.txt`
Get rid of the backticks.
echo ${var1} > yourname.txt
...for some reason when I run the script with sh myscript...
Don't run it that way. Make the script executable and run it directly
chmod +x myscript
./script
(or run with bash myscript explicitly).
It looks like that expression will work in bash but not in sh. As others pointed out change it to executable, make sure your shebang line is using bash and run it like this:
./myscript
If you want to run it with sh then it is complaining about line 5. Change it to this and it will work in /bin/sh.
if [ $# -ne 0 ]
Check out the man page for test.
Also you don't need the backticks on this line:
echo ${var1} > yourname.txt
Related
I am trying to compare strings in bash. I already found an answer on how to do it on stackoverflow. In script I am trying, I am using the code submitted by Adam in the mentioned question:
#!/bin/bash
string='My string';
if [[ "$string" == *My* ]]
then
echo "It's there!";
fi
needle='y s'
if [[ "$string" == *"$needle"* ]]; then
echo "haystack '$string' contains needle '$needle'"
fi
I also tried approach from ubuntuforums that you can find in 2nd post
if [[ $var =~ regexp ]]; then
#do something
fi
In both cases I receive error:
[[: not found
What am I doing wrong?
[[ is a bash-builtin. Your /bin/bash doesn't seem to be an actual bash.
From a comment:
Add #!/bin/bash at the top of file
How you are running your script?
If you did with
$ sh myscript
you should try:
$ bash myscript
or, if the script is executable:
$ ./myscript
sh and bash are two different shells. While in the first case you are passing your script as an argument to the sh interpreter, in the second case you decide on the very first line which interpreter will be used.
Is the first line in your script:
#!/bin/bash
or
#!/bin/sh
the sh shell produces this error messages, not bash
As #Ansgar mentioned, [[ is a bashism, ie built into Bash and not available for other shells. If you want your script to be portable, use [. Comparisons will also need a different syntax: change == to =.
if [ $MYVAR = "myvalue" ]; then
echo "true"
else
echo "false"
fi
I had this problem when installing Heroku Toolbelt
This is how I solved the problem
$ ls -l /bin/sh
lrwxrwxrwx 1 root root 4 ago 15 2012 /bin/sh -> dash
As you can see, /bin/sh is a link to "dash" (not bash), and [[ is bash syntactic sugarness. So I just replaced the link to /bin/bash. Careful using rm like this in your system!
$ sudo rm /bin/sh
$ sudo ln -s /bin/bash /bin/sh
If you know you're on bash, and still get this error, make sure you write the if with spaces.
[[1==1]] # This outputs error
[[ 1==1 ]] # OK
Specify bash instead of sh when running the script. I personally noticed they are different under ubuntu 12.10:
bash script.sh arg0 ... argn
Execute in your terminal:
sudo update-alternatives --install /bin/sh sh /bin/bash 100
Make the file executable and then execute without sh.
make it executable by $ chmod +x filename
then instead of sh filename use ./filename
On my server I try run:
#!/bin/bash
PATH="/SANCFS/stats/scripts/"
for (( i=6;i<=8;i++ ));
do
echo "Running $i"
exec "/SANCFS/stats/scripts/load_cdrs.sh --debug --config /SANCFS/stats/scripts/iquall-mm4-cdr.cfg --date '2018-10-0"$i"' >> /home/stats/201810/load_cdrsIMRMM4-0"$i".ok 2>>/home/stats/201810/load_cdrsIMRMM4-0"$i".err"
done
And the result is:
cannot execute: No such file or directory
Your help, how edit/modify to run successfully ?
Here's an easier way to reproduce your problem:
$ exec "echo "hello world""
bash: exec: echo hello: not found
Running a command in bash does not require adding exec or quotes:
$ echo "hello world"
hello world
Additionally, you are using $i in single quotes in one case, and you're overwriting the shell search path PATH for seemingly no reason. Applied to your example:
#!/bin/bash
for (( i=6;i<=8;i++ ));
do
echo "Running $i"
/SANCFS/stats/scripts/load_cdrs.sh --debug --config /SANCFS/stats/scripts/iquall-mm4-cdr.cfg --date "2018-10-0$i" >> /home/stats/201810/load_cdrsIMRMM4-0"$i".ok 2>>/home/stats/201810/load_cdrsIMRMM4-0"$i".err
done
Don't use exec. That replaces the current process with the process that runs the specified command, so you won't repeat the loop. Just execute the command normally.
And the argument to exec shouldn't be all inside a single quoted string. Maybe you're confusing it with eval?
#!/bin/bash
PATH="/SANCFS/stats/scripts/"
for (( i=6;i<=8;i++ ));
do
echo "Running $i"
/SANCFS/stats/scripts/load_cdrs.sh --debug --config /SANCFS/stats/scripts/iquall-mm4-cdr.cfg --date 2018-10-0"$i" >> /home/stats/201810/load_cdrsIMRMM4-0"$i".ok 2>>/home/stats/201810/load_cdrsIMRMM4-0"$i".err
done
You could replace exec with dot ( . )
If you try the 5 options, you should see the different options
$ exec /bin/bash
$ /bin/bash
$ . /bin/bash
$ ./bin/bash
$ /bin/bash /bin/bash
This is my sample Bash Script example.sh:
#!/bin/bash
# Reading arguments and mapping to respective variables
while [ $# -gt 0 ]; do
if [[ $1 == *"--"* ]]; then
v="${1/--/}"
declare $v
fi
shift
done
# Printing command line arguments through the mapped variables
echo ${arg1}
echo ${arg2}
Now if in terminal I run the bash script as follows:
$ bash ./example.sh "--arg1=value1" "--arg2=value2"
I get the correct output like:
value1
value2
Perfect! Meaning I was able to use the values passed to the arguments --arg1 and --arg2 using the variables ${arg1} and ${arg2} inside the bash script.
I am happy with this solution for now as it serves my purpose, but, anyone can suggest any better solution to use named command line arguments in bash scripts?
You can just use environment variables:
#!/bin/bash
echo "$arg1"
echo "$arg2"
No parsing needed. From the command line:
$ arg1=foo arg2=bar ./example.sh
foo
bar
There's even a shell option to let you put the assignments anywhere, not just before the command:
$ set -k
$ ./example.sh arg1=hello arg2=world
hello
world
#!/bin/bash
if [ ! -f readexportfile ]; then
echo "readexportfile does not exist"
exit 0
fi
The above is part of my script. When the current shell is /bin/csh my script fails with the following error:
If: Expression Syntax
Then: Command not found
If I run bash and then run my script, it runs fine(as expected).
So the question is: If there is any way that myscript can change the current shell and then interpretate rest of the code.
PS: If i keep bash in my script, it changes the current shell and rest of the code in script doesn't get executed.
The other replies are correct, however, to answer your question, this should do the trick:
[[ $(basename $SHELL) = 'bash' ]] || exec /bin/bash
The exec builtin replaces the current shell with the given command (in this case, /bin/bash).
You can use SHEBANG(#!) to overcome your issue.
In your code you are already using she-bang but make sure it is first and foremost line.
$ cat test.sh
#!/bin/bash
if [ ! -f readexportfile ]; then
echo "readexportfile does not exist"
exit 0
else
echo "No File"
fi
$ ./test.sh
readexportfile does not exist
$ echo $SHELL
/bin/tcsh
In the above code even though I am using CSH that code executed as we mentioned shebang in the code. In case if there is no shebang then it will take the help of shell in which you are already logged in.
In you case you also check the location of bash interpreter using
$ which bash
or
$ cat /etc/shells |grep bash
I am trying to compare strings in bash. I already found an answer on how to do it on stackoverflow. In script I am trying, I am using the code submitted by Adam in the mentioned question:
#!/bin/bash
string='My string';
if [[ "$string" == *My* ]]
then
echo "It's there!";
fi
needle='y s'
if [[ "$string" == *"$needle"* ]]; then
echo "haystack '$string' contains needle '$needle'"
fi
I also tried approach from ubuntuforums that you can find in 2nd post
if [[ $var =~ regexp ]]; then
#do something
fi
In both cases I receive error:
[[: not found
What am I doing wrong?
[[ is a bash-builtin. Your /bin/bash doesn't seem to be an actual bash.
From a comment:
Add #!/bin/bash at the top of file
How you are running your script?
If you did with
$ sh myscript
you should try:
$ bash myscript
or, if the script is executable:
$ ./myscript
sh and bash are two different shells. While in the first case you are passing your script as an argument to the sh interpreter, in the second case you decide on the very first line which interpreter will be used.
Is the first line in your script:
#!/bin/bash
or
#!/bin/sh
the sh shell produces this error messages, not bash
As #Ansgar mentioned, [[ is a bashism, ie built into Bash and not available for other shells. If you want your script to be portable, use [. Comparisons will also need a different syntax: change == to =.
if [ $MYVAR = "myvalue" ]; then
echo "true"
else
echo "false"
fi
I had this problem when installing Heroku Toolbelt
This is how I solved the problem
$ ls -l /bin/sh
lrwxrwxrwx 1 root root 4 ago 15 2012 /bin/sh -> dash
As you can see, /bin/sh is a link to "dash" (not bash), and [[ is bash syntactic sugarness. So I just replaced the link to /bin/bash. Careful using rm like this in your system!
$ sudo rm /bin/sh
$ sudo ln -s /bin/bash /bin/sh
If you know you're on bash, and still get this error, make sure you write the if with spaces.
[[1==1]] # This outputs error
[[ 1==1 ]] # OK
Specify bash instead of sh when running the script. I personally noticed they are different under ubuntu 12.10:
bash script.sh arg0 ... argn
Execute in your terminal:
sudo update-alternatives --install /bin/sh sh /bin/bash 100
Make the file executable and then execute without sh.
make it executable by $ chmod +x filename
then instead of sh filename use ./filename