Kill pids in a text file column

My program read  in and loop through a column in a text file that contains pids.  kill -9 kills all the pids in the column. The program errors and do not kill the pids in the column of foo4.txt .

set vi
while read $f1; do
    echo "$f1"
    kill -9 $f1
done < "/path/foo4"

The foo.txt: Contents  in the foo4.txt is as follows:

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The shebang must read "#!/bin/bash"
"read"  the variable "f1" not the variable's content "$f1"
"set vi" should  rather be "set -o vi", but is not meaningful in a script like this.

while read f1; do
    echo "$f1"
    kill -9 $f1
done < "/path/foo4"

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Gerwin Jansen, EE MVETopic Advisor Commented:
The loop is not really necessary, this should work as well:

kill -9 $(cat /path/foo4)
I just saw that the first line of your text file is "PID". You should get rid of this.

grep -v "PID" /path/foo4 | while read f1; do
    echo "$f1"
    kill -9 $f1

Or, following Gerwin's suggestion:

kill -9 $(grep -v "PID" /path/foo4)

Please note that the combined length of all arguments to "kill" plus the size of the environment
must not execeed ARG_MAX (check with "getconf ARG_MAX"), so for a very, very huge input file this might be safer:

grep -v "PID" /path/foo4 | xargs kill -9
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Shell Scripting

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