Question

the code is:

echo -n "Enter the number you want to search for"
read number1
for i in `seq 1 $N`
do
  temp= $number1
  if [ temp -eq ${array[$index]} ]
  then 
    temp= $index
  fi
done

echo " The position is" $temp

i donot get an output for this
just the position is and no number.
What am i doing wrong?

Answer 1

There are a few big problems here.

Whitespace in assignment. One problem is that these lines:

  temp= $number1

    temp= $index

need to be like this instead:

  temp=$number1

    temp=$index

This is because in Bash, something like this:

varname=value command

runs the command command with the environment variable varname set to value. In your case, this:

temp= $number1

tries to run the command $number1 with the environment variable temp set to the empty string.

Reuse of temporary variable. Another problem is that this line:

  temp=$number1

is run on every pass through the loop; so even if temp had previously been set to an appropriate array index, the above will discard that value and replace it with the number that the user had entered. Really, you should just remove this line, and use $number1 directly when you need it.

Variable-name mismatch. Another problem is that this line:

for i in `seq 1 $N`

uses i for the loop variable, but these lines:

  if [ temp -eq ${array[$index]} ]
  then 
    temp= $index

use index. Needless to say, these need to match.

Unexpanded variable. This line:

  if [ temp -eq ${array[$i]} ]

was surely meant to be this:

  if [ $temp -eq ${array[$i]} ]

(expanding the variable $temp instead of using the string 'temp'); but in light of the above, it should now be:

  if [ $number1 -eq ${array[$i]} ]

Array indices. Array indices start at zero; so if N is the number of elements in the array, then you need to iterate from 0 to N-1. So, this:

for i in `seq 1 $N`

needs to be this:

for i in `seq 0 $((N - 1))`

Though I actually think you should get rid of N entirely, and use ${#array[@]} (which is a Bash notation meaning “the number of elements in array) instead:

for i in `seq 0 $((${#array[@]} - 1))`