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string sed

[sed] Run and understand Add a string to a specified line number in a file

created-2025/12/15 updated-2026/03/24

Introduction

This repository runs the sed command to add a string to a specified line number in a specified file.

The commands you need to install

  1. git

Quickstart

If you have already installed the above command, run the following command to download it from the repository, then change the directory and run the sed command to check whether the string has been added to the specified file.

ubuntu

git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Output results
empty file

hello sed command world

empty file

macos

MacPorts

source ~/bashrc_folder/macports_alias
git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '' '1i\
hello sed command world\
' test.txt
cat test.txt
Output results
empty file

hello sed command world
empty file

windows

WSL2

git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Output results
empty file

hello sed command world

empty file

MSYS2 MINGW64

git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Output results
empty file

hello sed command world

empty file

Procedure

ubuntu

Click to open details

Advance confirmation

Enter the following command into the terminal and if command not found does not appear, it is OK.

git --version

preinstall

Please install the command that shows “command not found” in the terminal using the following command.

sudo apt install git

command

Executing the following command in the terminal should output a string similar to the following:

git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Detail
empty file

hello sed command world

empty file

macos

Click to open details

Advance confirmation

Enter the following command into the terminal and if command not found does not appear, it is OK.

source ~/bashrc_folder/macports_alias
git --version

*MacOS uses the MacPorts package manager to manage commands. If you haven’t installed it yet, please refer to the MacPorts installation instructions at the link below. Also, set an alias for the command so that you can call the command without conflicting with the existing environment. If you are using this blog for the first time, please refer to the following two articles to set up your environment.

preinstall

If the command not found appears in the terminal, install it using the following command and set an alias.

sudo port install git
echo 'alias git="/opt/local/bin/git"' >> ~/bashrc_folder/macports_alias

command

Executing the following command in the terminal should output a string similar to the following:

source ~/bashrc_folder/macports_alias
git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '' '1i\
hello sed command world\
' test.txt
cat test.txt
Detail
empty file

hello sed command world
empty file

windows

Click to open details

Advance confirmation

Enter the following command into the prompt and if command not found does not appear, it’s OK.

WSL2
git --version
MSYS2 MINGW64
git --version

*Windows has been confirmed to work with WSL2 and MSYS2 MINGW64. Please install WSL2 if possible, and if you are unable to set it up, you can run it by installing MSYS2, but there may be some commands that can only be run in WSL2. Please refer to the following article for instructions on how to install WSL2 and MSYS2.

preinstall

If the command not found appears in the prompt, please install it using the following command.

WSL2
sudo apt install git
MSYS2 MINGW64
pacman --sync git

command

By executing the following command at the prompt, you should get the following output:

WSL2
git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Detail
empty file

hello sed command world

empty file
MSYS2 MINGW64
git clone https://github.com/trygfmi/sed_write-file
cd sed_write-file
cat test.txt
sed -i '1i\
hello sed command world\
' test.txt
cat test.txt
Detail
empty file

hello sed command world

empty file

Afterword

Be sure not to forget to include a backslash () at the end of the sed command or the string you want to add.
If you want to expand and add a variable, use double quotes (“) as shown below.

number=1234
sed -i '' "1i\\
hello sed command world\\
$number
" test.txt
cat test.txt

List of how to use the sed command

There are other articles about the sed command besides this one.
Please check them out at the link below if you’re interested.

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