Delete lines containing pattern at the end of line

Question

Quite certainly I miss something basic. My file contains lines like

fooLOCATION=sdfmsvdnv

fooLOCATION=

barLOCATION=sadssf

barLOCATION=

and I want to delete all lines ending with LOCATION=.

sed -i '/LOCATION=$/d' file

does not do, it deletes nothing, and I have tried endless variations, but I don't get it. What inline sed command can do this?

Answer 1

There are two approaches here, either print all non-matching lines with

sed -in '/LOCATION=$/!p' file

or delete all matching names with

sed -i '/LOCATION=$/d' file

The first uses the n command line option to suppress the default action of printing the line. We then test for lines that end in LOCATION= and invert the pattern (only keeping those that don't match). When we get a desirable line, we print it with the p option.

The second looks for lines matching the end of line pattern, and deletes those that do.

Your file contains blank lines, and both of these keep those. If we don't want to keep those, we can change the first option to

sed -in '/^$/!{/LOCATION=$/!p}' file

which first checks if a line is not empty, and only bothers checking if it should be printed if it isn't empty. We can modify the second option to

sed -i '/^$/d;/LOCATION=$/d' file

which deletes blank lines and then checks about deleting the other pattern.

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We can modify the options to work with different line ending by specifying the difference in the pattern. The difference between line endings on Unix/Linux (\n) and Windows (\r\n) is the presence of an extra carriage return on Windows. Modifying the four commands above to accept either, we get

1. sed -in '/LOCATION=\r\{0,1\}$/!p' file
2. sed -i '/LOCATION=\r\{0,1\}$/d' file
3. sed -in '/^\r\{0,1\}$/!{/LOCATION=\r\{0,1\}$/!p}' file
4. sed -i '/^\r\{0,1\}$/d;/LOCATION=\r\{0,1\}$/d' file

Note that in each of these we allow an optional \r before the end of line. We use the curly bracket notation, as sed does not support the question mark optional quantifier in normal mode (using the r option to GNU sed for enabling extended regular expressions, we can replace \{0,1\} with ?).

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On a Windows shell, all of the options above require double quotes instead of single quotes.