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# sed Cheatsheet ## Overview sed (stream editor) is a Unix utility used to perform basic text transformations on an input stream (a file or input from a pipeline). It is a powerful tool for editing files in batch mode or in a script. ## Usage
sed [options] [script] [input_file]
## Options - `-n`: Suppress automatic printing of pattern space. - `-e script`: Add the script to the commands to be executed. - `-f script_file`: Add the commands contained in the script file to the commands to be executed. - `-i`: Edit files in place. - `-r`: Use extended regular expressions in the script. - `-h`: Do not print filenames when editing files in place. - `-V`: Display version information. - `-h`: Display help information. ## Commands - `s`: Replace the first occurrence of a pattern with a replacement string. - `g`: Replace all occurrences of a pattern with a replacement string. - `p`: Print the pattern space. - `d`: Delete the pattern space. - `a`: Append text to the output. - `i`: Insert text before the output. - `q`: Quit processing the input. - `r file`: Append the contents of a file to the output. ## Examples Replace the first occurrence of "foo" with "bar" in a file:
sed 's/foo/bar/' input_file.txt
Replace all occurrences of "foo" with "bar" in a file:
sed 's/foo/bar/g' input_file.txt
Delete lines that contain the word "foo" in a file:
sed '/foo/d' input_file.txt
Insert a line before the first line of a file:
sed '1i This is the first line.' input_file.txt
## Resources - [GNU sed Manual](https://www.gnu.org/software/sed/manual/sed.html) - [Sed - An Introduction and Tutorial](http://www.grymoire.com/Unix/Sed.html)