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Paul J
Paul J

Reputation: 777

csh/sh for loop - how to?

i'm trying to write a for loop that executes 2 scripts on FreeBSD. I don't care if it's written in sh or csh. I want something like:

for($i=11; $i<=24; $i++)
{
   exec(tar xzf 'myfile-1.0.' . $i);
   // detect an error was returned by the script
   if ('./patch.sh')
   {
      echo "Patching to $i failed\n";
   }
}

Does anyone know how to do this please?

Thanks

Upvotes: 7

Views: 70405

Answers (5)

William Pursell
William Pursell

Reputation: 212474

The typical way to do this in sh is:

for i in $(seq 11 24); do 
   tar xzf "myfile-1.0$i" || exit 1
done

Note that seq is not standard. Depending on the availability of tools, you might try:

jot 14 11 24

or

perl -E 'say for(11..24)'

or 

yes '' | nl -ba | sed -n -e 11,24p -e 24q

I've made a few changes: I abort if the tar fails and do not emit an error message, since tar should emit the error message instead of the script.

Upvotes: 7

gnudna
gnudna

Reputation: 1

Well what i just did is the following.

sh

Load sh shell and then for loop works like on linux.

for i in 1 2 3 4 5 6 7 8 9; do dd if=/dev/zero of=/tmp/yourfilename$i.test bs=52428800 count=15; done

Upvotes: -1

cdarke
cdarke

Reputation: 44394

csh does loops fine, the problem is that you are using exec, which replaces the current program (which is the shell) with a different one, in the same process. Since others have supplied sh versions, here is a csh one:

    #!/bin/csh
    set i = 11
    while ($i < 25)
        tar xzf "myfile-1.0.$i"

        # detect an error was returned by the script   
        if ({./patch.sh}) then     
            echo "Patching to $i failed"   
        endif
        @ i = $i + 1
    end

Not sure about the ./patch.sh are you testing for its existence or running it? I am running it here, and testing the result - true means it returned zero. Alternatively:

        # detect an error was returned by the script   
        if (!{tar xzf "myfile-1.0.$i"}) then     
            echo "Patching to $i failed"   
        endif

Upvotes: 4

David W.
David W.

Reputation: 107080

Wow! No BASH. And probably no Kornshell:

i=11
while [ $i -le 24 ]
do
    tar xzf myfile-1.0.$i
    i=`expr $i + 1`
    if ./patch.sh
    then
        echo "patching to $i failed"
    fi
done

Written in pure Bourne shell just like God intended.

Note you have to use the expr command to add 1 to $i. Bourne shell doesn't do math. The backticks mean to execute the command and put the STDOUT from the command into $i.

Kornshell and BASH make this much easier since they can do math and do more complex for loops.

Upvotes: 5

Axel
Axel

Reputation: 14169

I think you should just use bash. I don't have it here, so it cannot test it, but something along this should work:

for ((I=11; I<=24; I++)) ; do
   tar xzf myfile-1.0.$I || echo Patching to $I failed
done

EDIT: Just read the comments and found out there's no bash in FreeBSD default installation. So this might not work at all - I'm not sure about the differences between (t)csh and bash.

Upvotes: -1

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