Following is my shell ：
d=$(date "+%y:%m:%d:%H:%M:%S")
i=0
for dbname in $(cat $MONCONF/db_name|head -n 200)
do (
result=`remsh dbsvr1 ". /home/db2inst2/sqllib/db2profile;db2 get snapshot for all on $dbname"`
echo $result|grep "High water mark for connections">1.txt
)
((i=i+1))
done
when I execute this shell,the error is generated：
grep: 0652-226 Maximum line length of 2048 exceeded.
How to resolve it?
Thanks!

remsh dbsvr1 ". /home/db2inst2/sqllib/db2profile;db2 get snapshot for all on $dbname" | grep "High water mark for connections">1.txt

or

result=`remsh dbsvr1 ". /home/db2inst2/sqllib/db2profile;db2 get snapshot for all on $dbname"`
echo "$result" |grep "High water mark for connections">1.txt

It is done.
However,when I modify the shell as followings:
d=$(date "+%y:%m:%d:%H:%M:%S")
i=0
for dbname in $(cat $MONCONF/db_name|head -n 200)
do (
result=`remsh dbsvr1 ". /home/db2inst2/sqllib/db2profile;db2 get snapshot for all on $dbname"`
echo $result|grep -E "High water mark for connections|database name">1.txt
)
((i=i+1))
done
the following error occurs.
./db2_connect.sh[10]: 0403-029 There is not enough memory available now.
./db2_connect.sh[6]: 0403-029 There is not enough memory available now.
grep: 0652-226 Maximum line length of 2048 exceeded.

Why?
What's the differenc between "$result" and $result?

Quotes are *very* important in Unix. You should probably read up on them because the way you quote anything, using single quotes, double quotes, backticks and/or any combination of these can produce completely different results.

In this example, not quoting $result, causes the shell to perform variable expansion on $result, the resulting string is then tokenised using the values held in the environment variable $IFS ( by default a space, a tab and a newline ). Effectively, this means that all the spaces, tabs and newlines in $result would be lost and replaced with a single space. Using quotes would cause $result to be treated as a single token, thus retaining the embedded spaces, tabs and newlines.

e.g.

$ var="a
$ b
$ c"
$ echo $var
a b c
$ echo "$var"
a
b
c

thanks a lot.
I have understand the importance of double quota.
However,how to resolve this problem
the following error occurs.
./db2_connect.sh[10]: 0403-029 There is not enough memory available now.
./db2_connect.sh[6]: 0403-029 There is not enough memory available now.
grep: 0652-226 Maximum line length of 2048 exceeded.

Why?