Delete a specific line from a text file with sed

At some point you may have the need to remove all lines within a text file that match a certain pattern. Accomplishing this is easy with the sed command.

Here is the command format.

$ sed -i '/PATTERN/ d' file.txt

• The ‘-i‘ option allows you to edit the specified file in place.
• PATTERN is a regular expression
• d is a command which instructs sed to delete the line if it matches the PATTERN

Here is an example.

$ cat file.txt

one
two
three
one hundred

We want to remove the lines containing the word “one”

$ sed -i '/one/ d' file.txt

$ cat file.txt

two
three

If your pattern contains an environment variable, you can surround it with double quotes instead to force the shell to expand it.

$ sed -i "/$MYVAR/ d" file.txt