Add number in a bash script

Question

I have a folder containing file file1.png, file2.png, ..., file5.png. I'd like to copy them into a new folder and rename them as file6.png to file10.png. The bash script I used was:

for i in `seq 1 5`;
k=$((i+5));
do cp src/file$i.png dst/file$k.png;
done;

However, the line k=$((i+5)) always says syntax error. Any ideas?

do should come before k=$((i+5))

anubhava
– anubhava

2016-09-01 07:47:31 +00:00
Commented Sep 1, 2016 at 7:47 — anubhava
– anubhava, Commented Sep 1, 2016 at 7:47
shellcheck.net/# helps in such cases...

Sundeep
– Sundeep

2016-09-01 08:38:58 +00:00
Commented Sep 1, 2016 at 8:38 — Sundeep
– Sundeep, Commented Sep 1, 2016 at 8:38
As written, the semi-colons are totally unnecessary.

user3439894
– user3439894

2016-09-01 12:11:10 +00:00
Commented Sep 1, 2016 at 12:11 — user3439894
– user3439894, Commented Sep 1, 2016 at 12:11

sjsam · Accepted Answer · 2016-09-01 08:37:25Z

4

Below script do the job :

for i in {1..5}
do # You need to put 'do' just after the for statement
cp src/file"$i".png dst/file"$((i+5))".png
done

Notes

See [ brace expansion ] to know more about {START..END}.
Note $((i+5)) returns the result to where it is called from, so you may avoid using the intermediate variable k.

edited Sep 1, 2016 at 8:37

answered Sep 1, 2016 at 7:59

sjsam

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Comments

Ohad Eytan · Accepted Answer · 2016-09-01 09:06:22Z

1

You forgot the do after the for:

for i in `seq 1 5`; do k=$((i+5)); echo $k; done;
#output:         ---^---
6
7
8
9
10

edited Sep 1, 2016 at 9:06

answered Sep 1, 2016 at 7:49

Ohad Eytan

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Comments

Chem-man17 · Accepted Answer · 2016-09-01 12:25:11Z

1

You have to do this-

for i in `seq 1 5`
do
k=$(($i+5))
cp src/file"$i".png dst/file"$k".png
done

edited Sep 1, 2016 at 12:25

answered Sep 1, 2016 at 7:47

Chem-man17

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3 Comments

sjsam Over a year ago

No harm omitting $ inside ((..)).

user3439894 Over a year ago

As written, the semi-colons are totally unnecessary.

Chem-man17 Over a year ago

@user3439894, yup you're right. I was lazy during my copy pasting. I changed a one liner to a multi line comment for greater readability. Removed the semi colons now.

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