Description: The tee command is a fundamental tool in the shell scripting environment, especially in Unix-like operating systems. Its main function is to read data from standard input and simultaneously write that data to both standard output and one or more files. This allows users to capture the output of a command while also displaying it in the terminal. The name ‘tee’ comes from the way the command splits the data stream, similar to a ‘T’ in plumbing, where the flow bifurcates in two directions. Tee is particularly useful in scripts and automation tasks, where there is a need to log the output of a process while still displaying it on screen. Additionally, the command can accept multiple files as arguments, making it a versatile tool for data and log management. Its simplicity and effectiveness have made it an essential component in the toolbox of any system administrator or developer working in command-line environments.
History: The tee command was introduced in the Unix operating system in the 1970s. Its development is part of the evolution of command-line tools aimed at improving efficiency in data manipulation. As Unix gained popularity, the tee command became an integral part of shell scripts, allowing users to manage command output more effectively. Over time, tee has been adopted in various Unix variants and Linux-based operating systems, maintaining its relevance today.
Uses: The tee command is primarily used to log command output to files while displaying it in the terminal. This is especially useful in script debugging, where developers may want to see output in real-time and also save it for later analysis. Additionally, tee can be used in combination with other commands through pipes, allowing for the creation of more complex and efficient workflows in the command line.
Examples: A practical example of using tee is as follows: if you want to save the output of a file listing command to a file while displaying it in the terminal, you can use: ‘ls -l | tee listing.txt’. This will create a file called ‘listing.txt’ with the content of the file listing and simultaneously display the same content in the terminal. Another example would be: ‘echo “Hello World” | tee file.txt file2.txt’, which would save the text to two different files.
