Shell Programming and Scripting

I know this doesn't work, my question is how to do the, if not, THEN in sed? I guess I use the branching but had less than success with it, anyway let me know.

Code:

sed -n 'p;/{/ !s/^/#/; s/^\(.*\)/# \1/' file6

If not

Code:

{

then add

Code:

#

with the other sustitute statement. Thanks

P.S. Simply put, If I am too confusing maybe show me how to do this particular example with sed, the original question.

That is not the original question. The original question was how to put an octothorps at the start of every line that contains the string beautiful. The obvious way to do that in sed is:

Code:

sed '/beautiful/s/^/#/' file

but the original request was also to put the results back in the input file. Just using standard sed features (i.e., no -i option), that can be done with:

Code:

sed '/beautiful/s/^/#/' file > file.$$ && cp file.$$ file;rm -f file.$$

But, if you did want to add an octothorpe to the lines that do NOT contain beautiful, you can do that in sed with:

Code:

sed '/beautiful/n;s/^/#/' file

Sorry Don will ask the question as a new one,
thanks

Code:

while read line
do
   echo "$line" |grep beautiful >/dev/null 2>&1
   if [ $? = 0 ]
   then
     echo "#$line"
   else
     echo "$line"
   fi
done <a.sh

If you want to write it using a script.

Rudic can you explain !s
sed '/{/ !s/^/#/' file

From the standards: Or, translated from standardese, perform the specified substitution (insert an octothorpe at the start of a line) on lines that do not contain an open brace character.