vi editor for loop syntax problem

Asked by Suman Mitra on 2013-09-25

for (( i=0; i<=5; i++ ))
do
        echo "$i Echoed"
done

this is what wrote in "bubble.sh" with vi editor and it gave me this error "bubble.sh: 1: bubble.sh: Syntax error: Bad for loop variable
"
i don't seem to understand why this is happening..please help

Question information

Language:
English Edit question
Status:
Answered
For:
Ubuntu gnome-terminal Edit question
Assignee:
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Last query:
2013-09-27
Last reply:
2013-09-27
Ubfan (ubfan1) said : #1

Your code is just fine and works FOR BASH. Look a t the beginning of your script, and if you have a #!/bin.sh, you are not even running bash. Change it to #!/bin/bash

Thomas Kr├╝ger (thkrueger) said : #2

You have to add

#!/bin/bash

as the first line.

details: http://www.tldp.org/LDP/abs/html/sha-bang.html

or you can run:

sh bubble.sh

The file extension means NOTHING in Linux. It's always confused me why people feel the need to add them. This isn't Windows. You can rename a .jpg to a .png and the OS will still see a jpeg format image.

The file is a list of instructions, but the shell has no idea what interpreter to use, so it complains. Adding:

#!/bin/bash

As people have said tells the system to use sh as the interpretter and it will run, you can code in python and use:

#!/usr/bin/python

In the same manner. Remember to also mark the file as executable.

andy@fileserver:~$ nano t; chmod +x ./t
andy@fileserver:~$ ./t
0 Echoed
1 Echoed
2 Echoed
3 Echoed
4 Echoed
5 Echoed
andy@fileserver:~$ cat ./t
#!/bin/bash
for (( i=0; i<=5; i++ ))
do
        echo "$i Echoed"
done

Just so you know it works :)

Suman Mitra (sumanmitra97) said : #5

#!/bin/bash
for (( i=0; i<=5; i++ ))
do
        echo "$i Echoed"
done
 i wrote this and this showed up....
"suman@Cyber-Poision:~$ sh bubble.sh
bubble.sh: 2: bubble.sh: Syntax error: Bad for loop variable"

still doesn't work... :(

Try:

chmod +x ~/bubble.sh; ~/bubble.sh

Does it then run?

What is the output of:

cat /etc/issue

Thanks

Suman Mitra (sumanmitra97) said : #7

suman@Cyber-Poision:~$ chmod +x ~/bubble.sh; ~/bubble.sh
0 Echoed
1 Echoed
2 Echoed
3 Echoed
4 Echoed
5 Echoed
suman@Cyber-Poision:~$ cat /etc/issue
Ubuntu 12.04.3 LTS \n \l
 it worked with the first command i don't get it...what's going on..??

If you mark the file as executable it will be treated as a script. You have the right header so now the 'sh' bit you were using to attempt to run it with is not needed. The '.sh' file extension does nothing at all for the file, its just a naming convention Windows users seem to hang on to as they seem to refuse to have files without file extensions. Weird really

Suman Mitra (sumanmitra97) said : #9

Oh.I get it.But now when i removed the extension and wrote "sh bubble" it says this "bubble: 2: bubble: Syntax error: "(" unexpected".What do i need to do work around that?

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