Editing a File with SED

jschiwal · 05-18-2008, 08:05 AM

A) for var test. This probably won't work. Do you want
for var in $(cat test)

Also, test is a bad name to use because it is the name of a builtin. This is especially true if you tried to use test as the name of a file or alias.

Also, you are matching lines that contain the characters of the number and not deleting that line itself.

If you want to delete a particular line in sed;
sed -i "${line}d" file

If $line is 3, this will be evaluated as:
sed -i 3d file

pixellany · 05-18-2008, 08:05 AM

Quote:

Originally Posted by SBN

What does the code do?

It does exactly what it says it does!!! Seriously, what part do you not understand?

In addition to the documentation already suggested, my favorite SED tutorial is here: http://www.grymoire.com/Unix/Sed.html

The thing that might be hard to see is the use of a "backreference". Here is a generic example:

sed 's/stuff$keepthis$morestuff/ newstuff\1/'
The output of this will be: "keepthis newstuff". Anything between the escaped parentheses ("") is inserted where the "\1" appears.