CODEWITHSUNDEEP
bashshellsh
emarwa.mouma.35t
emarwa.mouma.35t

Reputation: 89

Loop does not work normally in git action

Loop does not work normally in git action.

My task.sh looks like this:

#!/bin/bash

range=100
number=$((RANDOM % range))

while [ "$i" -le "$number" ]; do
    echo "DATE: $1" >> date.txt
done

The result of the above code is:

./task.sh: 6: [: Illegal number:

The code below works fine.

echo "DATE: $1" >> date.txt

I tried the following, but it also gives an error.

#!/bin/bash

range=500
number=$((RANDOM % range))

for ((run=1; run <= number; run++)); do
    echo 'hello'
done

I'm curious how you can make a command like below work normally.

while (random(1-100)); do
     echo 'hello'
done

Best regards!

Upvotes: 1

Views: 495

Answers (2)

VonC
VonC

Reputation: 1326782

It should work fine with:

while [[ "$i" -le "$number" ]]; do
      ^^                    ^^

This requires bash, but since your shebang is #!/bin/bash, your t.sh script will run with bash, no matter its '.sh' extension.

But in its current form, it would be an infinite loop.

You would need to add

i=$((i+1))

That would increment the $i variable, making "$i" -le "$number" work properly.

Initializing i to 0 is better/cleaner, but [[ "" -le "$number" ]] (on the first loop, still "works" (in that an empty string is consider "lower or equal" to an non-empty "$number" string, and remains in the loop)

That being said, the more correct form/usage for that script would be (using arithmetic comparison):

#!/bin/bash

range=100
number=$((RANDOM % range))
i=0

while (( i <= number )); do
    echo "DATE: ${i}" >> date.txt
    i=$((i+1))
done

Or, using a c-style loop

#!/bin/bash

range=100
number=$((RANDOM % range))

for ((i = 0 ; i < number ; i++)); do
    echo "DATE: ${i}" >> date.txt
done

All this assumes bash, but as seen here, since for (( ... )) syntax isn't POSIX, it would not work with Alpine Linux or other OS where sh links to ash (Almquist shell) or Dash.

In that latter case:

#!/bin/bash

range=100
number=$((RANDOM % range))

for i in $(seq 0 $number); do
    echo "DATE: ${i}" >> date.txt
done

Upvotes: 3

that other guy
that other guy

Reputation: 123560

You have two separate problems:

  1. You are running your script with sh, not bash
  2. You are not assigning i

For the first one, see Why does my Bash code fail when I run it with 'sh'?

For the second, set i=0 in your script before you try to compare $i as a number.

Upvotes: 2

Related Questions