Operating on Lines by Number
Learn how to perform operations on lines in a file by their number.
Finding a line
We usually find a line with text or a regular expression, but we can also find it by its number. Let’s go back to the urls.txt
file and explore this further.
Let’s comment on the first line of the file. We use the following command to target the first line and insert the comment character:
$ sed -e '1 {s/^/#/}' urls.txt
To comment on lines 2 through 4 of the file, we use the following command that specifies a range:
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