As far as I know there is no prepend operator on a bash or any other shell, however there are many ways to do the same. echo "$(echo 'task goes here' | cat - todo.txt)" > todo.txt It's impossible to add lines to the beginning of the file without over writing the whole file. And it goes without saying that the most popular command line tools for this in Linux are sed and awk – the two best text processing programs.. For the last line it's again traversing the entire file and appending a last line. Append a prefix in front of every line of a file. So, the lines will be added to the file AFTER the line where condition matches. Add a line in a specific position with Linux. If you need to add a line to a file in Linux, and you need to add that line in a specific position of the file there is an easy solution, even if you need to do it to hundreds of thousands of files. Here is simple solution using a temporary file to prepend text: sed "i" command lets us insert lines in a file, based on the line number or regex provided. You can use the cat command on either of these files to display their contents. You can use multiple methods to write multiple lines to a file through the command line in the Linux system. If the text file is small enough to fit in memory, you don't have to create a temporary file to replace it with. In the following script, an existing file, books.txt is assigned to the variable, filename, and a string value will be taken as input from the user to add at the end of the file. Bash prepend a text using a temporary file. Method 1:-You can write/append content line by line using the multiple echo commands. Since its very huge file (14GB) this is taking very long time. Add character at the beginning of each line using sed command. Sometimes you may be required to write or append multiple lines to a file. From time to time it is required to modify some file very fast. But the issue with this command is that it is appending the first line of the file and traversing entire file. Here are the three methods described below. To extract lines one to four, we type this command: sed -n '1,4p' coleridge.txt. If the input value is not empty, then the ‘echo’ command will append the value into the books.txt file by using ‘>>’ symbol. Here we will add a text “PREFIX:” in front of every line of my file # sed -ne 's/. Linux: Using sed to insert lines before or after a match The sed utility is a powerful utility for doing text transformations. Consider this file: line 1 line 2 line 4 Example-1: Append line to the file using ‘echo’ command and ‘>>’ symbol. To start the editor in a Linux system, type vi followed by the name of the file you want to edit, like this: vi /etc/fstab The vi editor loads the file into memory, displays the first few lines in a text screen, and positions the cursor on the first line. You can load it all into memory and write it back out to the file. You can use ed, sed, perl, awk and so on to add text to the beginning of a file in Bash under Linux or Unix-like systems. To add a single line of text, enter: printf ‘First line of text\n’ test5.txt. In the following article, you’ll find an information about how to add some text, character or comma to the beginning or to the end of every line in a file using sed and awk. A single number selects that one line. In this article, I will provide an example of how to insert a line before and after a match using sed, which is a common task for customizing configuration files. 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