syntax of for loop in linux shell scripting

Question

I have a problem implementing a for loop. I get this error when I execute my script

test1.sh: 2: Syntax error: Bad for loop variable

I don't understand this error.

This is my script

#!/bin/bash
for (( c=1; c<=5; c++ ))
do
echo "Welcome $c times..."
done

can any one tell me syntax for for loop in sh(in ubuntu it links to dash shell) shell in ubuntu?

Answer 1

You probably run it with sh, not bash. Try bash test1.sh, or ./test1.sh if it's executable, but not sh test1.sh.

Answer 2

A standard POSIX shell only accepts the syntax for varname in list

The C-like for-loop syntax for (( expr1; expr2; expr3 )) is a bashism.

You can get similar behavior in the standard POSIX shell using for c in $(seq 1 5)

Answer 3

What does

ls -l /bin/sh

give on your machine ?

Make sh a symbolic link to bash and then you can do sh ./test1.sh