Shell Programming and Scripting

Yes,
I'm able to get the output now. Thank You
Now i had an issue with If condition inside loop
I tried like below and getting error : not found

Code:

file="/etc/nms.txt"
chek="ABCD"
# while loop
while read line
do
        # display line or do somthing on $line
        echo "$line"
         if ["$chek" == "$line" ]
           then
            echo "Equal"
         fi
done <"$file"

Where i'm doing wrong here. Please advice

Please put space between square brackets.

like

Code:

if [ "$chek" == "$line" ]

Try this,

Code:

file_nm="/etc/nms.txt"
mLine="ABCD"
cat $file_nm|while read line
do
echo $line
            if [ $mline == $line ]
            then
                  echo $mLine
            fi
done

This should solve your purpose

Because of field splitting, this will loop over words, not lines.

This doesn't even read the file. It merely echoes the file name, possibly breaking it into pieces if it contains whitespace, then echoes the pieces of the file name. Not a single line of the file's contents is read.

This won't loop over the lines of the file. The entire file's contents will be assigned en masse to i and the loop will iterate at most once (if the file is empty, it won't iterate at all). A functional equivalent:

Code:

i=$(cat $file)
[ "$i" ] && echo "$i"

By far the best suggestion, but it's still inadequate for arbitrary text ("arbitrary" being the operative word).

To preserve leading and trailing whitespace, IFS should be unset in read's environment.

To prevent backslashes from being treated specially, read's raw mode should be used.

echo is unsuitable for printing arbitrary text. echo does not support -- to signal the end of option processing. If the arbitrary text looks like a valid option, the output will be mangled. printf should be used instead.

Finally, $data should be quoted to preserve its whitespace.

Code:

while IFS= read -r data; do
    printf '%s\n' "$data"
done

Regards,
Alister