problem with for loop in BASH script

Question

I'm trying to execute the following loop inside my script in order to send mail to all users in a certain file that I write in earlier in the script. I check if the file $eUsers is not empty I execute the following:

for name in `cat $eUsers | cut -d' ' -f2`
do
echo "message" > /letter
cat /letter | mail -s "message" $name
done

At the beginning of the script I define $eUsers= "/filename".
The code : cat $eUsers | cut -d' ' -f2 gets back the user name. I tried it out in the terminal, and it's working. I tried putting the above code in a separate file and replaced "$eUsers" with its path (/filename), and it worked without any problems.

However, when I use that code in my script, after writing in the file $eUsers, it goes into an infinite loop. I dont' understand why it's doing so. In the original file, the infinite loop seems to occur because of the line cat /letter | mail -s "message" $name.

try running your script with -x option #!/bin/bash -x at the top so you can view a verbose output. — Anders
– Anders, Commented Dec 28, 2010 at 23:12
There's nothing in the script as posted that should cause an infinite loop. I'm assuming that /letter (and /filename) represents a longer path since it would be unusual to put a file directly in the root directory. I'm also assuming that there's some reason that you output the message to a file, since echo "message" | mail ... would work without needing a file. If you try the -x as suggested it may show you where the problem is or if you can post more details we may be better able to help. I think it's probably some other part of the code that is actually causing the problem. — Dennis Williamson
– Dennis Williamson, Commented Dec 29, 2010 at 2:33

SiegeX · Accepted Answer · 2010-12-29 04:15:03Z

2

#!/bin/bash

while read junk name; do
  echo "message" | mail -s "message" "$name"
done < "$eUsers"

answered Dec 29, 2010 at 4:15

SiegeX

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