Shell Programming and Scripting

Hello everyone,

I am trying to replace a word by another using shell programming.

for that, I can use

sed -i 's/second_word/first_word/' file_name

but for me,the problem is that I don't know one of the words, It is present in a variable that are created dynamically by the script.

for example

I have a line in the file

127.1.1.1 root localhost localcomp

Here root is my hostname

I want to replace the hostname 'root' with a different hostname.

Script will ask the user to provide the hostname and keeps it in a variable '$hostname'

I want to replace this 'root' with '$hostname'

Can anyone help me with this.

Thanx in advance..

--Sunny

One suggestion. Create a skeleton script that you build the new script from.

give your line this format

127.1.1.1 <hostname> localhost localcomp

Replace this variable with what is entered by the user and write to a new file

sed -e "s/<hostname>/$hostname/" < skeleton.file > updated.file

I have tried that, the problem is that the replacement function

s/<hostname>/$hostname/


It is not taking the value of the variable, instead it is printing the '$hostname' in the output file.

Is there anyway I can avoid that.

--Sundeep

I just tried the following and works like a charm...

Code:

sed "s/root/$hostname/" input.txt

or

sed "s/root/$hostname/" input.txt > output.txt

Make sure the its the "double quotes"

'single tick' will not resolve the $hostname

Thanx a lot hemang. I appreciate your help.

--Sundeep