Sed -I In Shell Script Top 3 Favorites

The sed command is a powerful utility in Unix/Linux systems used for text manipulation, including editing files in place. The -i option is used to specify that the changes should be made directly in the file, without creating a backup file.

In a shell script, you can use sed -i to modify a file’s contents without requiring manual editing. Here’s an example of how to use sed -i in a shell script:

bash
#!/bin/bash

# Replace all occurrences of "foo" with "bar" in the file named "myfile.txt"
sed -i 's/foo/bar/g' myfile.txt

# Append a line to the end of the file named "myfile.txt"
sed -i '$a\This is a new line' myfile.txt

# Delete all lines containing the word "error" in the file named "logfile.txt"
sed -i '/error/d' logfile.txt

In each of these examples, sed -i is used to modify the specified file directly, without creating a backup. It’s important to use caution when using sed -i because any changes made to the file are permanent and cannot be undone. It’s a good practice to create a backup of the file before using sed -i to modify it, in case you need to revert the changes later.

The “sed -i” command is used to perform an in-place modification of a file by replacing a particular pattern with another string. The “-i” option stands for “in-place” and it tells the sed command to make changes directly to the file instead of printing the output to the console.

Here is an example of how to use the “sed -i” command to replace a pattern with another string in a file:

python
sed -i 's/pattern/replacement/g' filename

In this command, “pattern” is the string that you want to replace, “replacement” is the new string that you want to replace it with, and “filename” is the name of the file that you want to modify. The “g” at the end of the command stands for “global” and tells sed to replace all occurrences of the pattern in the file.

For example, let’s say you have a file called “example.txt” that contains the string “hello world”. You can use the following command to replace “hello” with “hi”:

python
sed -i 's/hello/hi/g' example.txt

After running this command, the contents of “example.txt” will be “hi world”.

The “sed -i” command is used in Unix/Linux systems to modify a file in place. Here’s an example:

Suppose you have a file called “example.txt” with the following content:

python
This is line 1
This is line 2
This is line 3

And you want to replace “line” with “row” in the file. You can use the following command:

python
sed -i 's/line/row/g' example.txt

This command will replace all occurrences of “line” with “row” in the file “example.txt”. The “-i” flag indicates that the file should be edited in place, meaning the changes will be made directly to the file instead of being displayed on the screen.

After running the command, the content of the file will be:

python
This is row 1
This is row 2
This is row 3

Note that the original file is modified and the changes are saved in place. It’s always a good idea to make a backup of the original file before making changes with “sed -i”.