sed Command in Linux

Linux sed Command Syntax

The syntax for the sed command is as follows:

Where:

• OPTIONS: The available options for the sed command
• SCRIPT: A set of sed commands to be executed on the input file.
• FILE: The file to be processed by the sed command.

sed Command Options:

• -i: Edit files in place
• -e: Add the script to the commands to be executed
• -n: Suppress automatic printing of pattern space
• -f: Add the contents of a script file to the commands to be executed

Example Usages

• Substitute a pattern with another pattern in a file:

  Output:

  Explanation: This command replaces all occurrences of the pattern 'pattern' with the replacement 'replacement' in the file 'file.txt'. The 'g' flag indicates that the replacement should be global, meaning all occurrences of the pattern in the file should be replaced.

• Print specific lines in a file:

  Output:

  Explanation: This command prints the second to fourth lines of the file 'file.txt'. The '-n' option suppresses the automatic printing of the pattern space. The 'p' command prints the pattern space.

• Delete a specific line in a file:

  Output:

  Explanation: This command deletes the third line of the file 'file.txt'. The 'd' command deletes the pattern space.

Advanced Use Cases of sed Command in Linux

• Replace a pattern in multiple files:

  Output:

  Explanation: This command replaces all occurrences of the pattern 'pattern' with the replacement 'replacement' in all .txt files in the current directory. The '-i' option edits the files in place.

• Insert text at the beginning of a line:

  Output:

  Explanation: This command inserts the text 'prefix' at the beginning of each line in the file 'file.txt'. The '^' character represents the beginning of a line.

• Print lines that match a pattern:

  Output:

  Explanation: This command prints all lines that contain the pattern 'pattern' in the file 'file.txt'. The '/pattern/' regular expression matches lines that contain the pattern. The 'p' command prints the pattern space.