When to use sed to replace a multi-line string?
Theoretically speaking, there is no upper limit on the size of the pattern space window. When the file size is small, we can practically afford to load the entire file into the pattern space to replace a multi-line string. So let’s learn this gobbling technique to solve some use cases.
Table of Contents
How to get only the replaced string from a multiline input?
sed – Get only the replaced string from a multi-line input and skip unmatched lines. I want sed to skip all lines that don’t match, and only output the replaced string (of the intended single/multiple lines). In other words: I have a lot of hay, and I just want the needle back, not all the hay that was fetched and left undisturbed.
What is the command for multiline operations in SED?
sed has three commands to handle multiline operations: N, D, and P (compare them to the normal n, d, and p). In this case, you can match the first line of your pattern, use N to add the second line to the pattern space, and then use s to do your substitution.
How does SED rename a file?
By default, sed reads the file line by line, changing only the first occurrence of SEARCH_REGEX on a line. When the replacement flag is supplied, all occurrences are replaced. INPUTFILE – The name of the file on which you want to run the command.
How to replace multiple lines in a Linux file?
There are different commands in Linux to replace multiple lines of a file. The `sed` command is one of them to perform this kind of tasks. The full form of `sed` is the Steam Editor, and is mainly used to read and convert text in different ways using a regular expression.
How to slip pattern space in Linux SED?
Finally, we can scroll the pattern space window using the d command at the end of the current read cycle, followed by two invocations of the N command on the next read cycle: In this way, the read cycles will continue until there are no more employee records to read.
