Loop variable error in for loop

Question

When I’m using for like

 for i in 1 2 3 4 5

then my file contains #!/bin/sh at the top.

But when I’m using

for(( i = 0; i<=5; i++))

then it is showing error

Syntax error: Bad for loop variable

and running properly when I remove shebang. Please tell me the reason behind this.

score 12 · Accepted Answer · answered Jan 06 '14 at 12:05

12

for(( i = 0; i<=5; i++)) is Bash specific and doesn't work with plain Bourne shell (/bin/sh).

If you remove the shebang the script is run by your current shell (which likely is Bash) so it works.

Replace #!/bin/sh with #!/bin/bash to make the shebang work.

answered Jan 06 '14 at 12:05

Florian Diesch

87,389

Is there any way to do it in sh mode? Thanks! – Ziyaddin Sadygly Feb 26 '14 at 18:48
2

i=0; while [ $i -le 5 ]; do echo $i; i=$((i+1)); done – Florian Diesch Feb 26 '14 at 19:32
1

I use #bash already and not works – Bruno Jun 23 '18 at 01:33

score 2 · Answer 2 · answered Nov 21 '16 at 18:12

2

I have solved this problem by using ./ instead of sh command. For an example if you put sh test.sh instead just make your command as ./test.sh And most probably problem will be solved.

answered Nov 21 '16 at 18:12

dilantha111

121
3

score 2 · Answer 3 · edited May 23 '17 at 12:39

2

for(( i = 0; i<=5; i++))

for this type of loop only runs on Bash shell. so, if you want to run this, then try this command :

$bash filename.sh

I think It will work fine. and see this one also.

edited May 23 '17 at 12:39

Community

1

answered Mar 27 '17 at 11:15

Sudip Das

300

score 0 · Answer 4 · edited Jan 17 '14 at 14:29

0

Try this out may be this could solve your problem

#!/bin/bash
j=0
for (( i=1; i <= 5; i++ ))
do
 echo "the loop is runing $i time: and value of j is $j"
 j=`expr $j + 1`
done

edited Jan 17 '14 at 14:29

Florian Diesch

87,389

answered Jan 16 '14 at 11:55

smn_onrocks

526
5
14

Loop variable error in for loop

4 Answers4