From 3774f144c81fbe522139658c38ea470f4fd2cd14 Mon Sep 17 00:00:00 2001 From: DarkSun Date: Sun, 22 Nov 2020 05:02:18 +0800 Subject: [PATCH] =?UTF-8?q?=E9=80=89=E9=A2=98[tech]:=2020201122=20How=20to?= =?UTF-8?q?=20Save=20the=20Output=20of=20a=20Command=20to=20a=20File=20in?= =?UTF-8?q?=20Linux=20Terminal=20[Beginner=E2=80=99s=20Tip]?= MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit sources/tech/20201122 How to Save the Output of a Command to a File in Linux Terminal -Beginner-s Tip.md --- ... File in Linux Terminal -Beginner-s Tip.md | 114 ++++++++++++++++++ 1 file changed, 114 insertions(+) create mode 100644 sources/tech/20201122 How to Save the Output of a Command to a File in Linux Terminal -Beginner-s Tip.md diff --git a/sources/tech/20201122 How to Save the Output of a Command to a File in Linux Terminal -Beginner-s Tip.md b/sources/tech/20201122 How to Save the Output of a Command to a File in Linux Terminal -Beginner-s Tip.md new file mode 100644 index 0000000000..1abd6c775d --- /dev/null +++ b/sources/tech/20201122 How to Save the Output of a Command to a File in Linux Terminal -Beginner-s Tip.md @@ -0,0 +1,114 @@ +[#]: collector: (lujun9972) +[#]: translator: ( ) +[#]: reviewer: ( ) +[#]: publisher: ( ) +[#]: url: ( ) +[#]: subject: (How to Save the Output of a Command to a File in Linux Terminal [Beginner’s Tip]) +[#]: via: (https://itsfoss.com/save-command-output-to-file-linux/) +[#]: author: (Abhishek Prakash https://itsfoss.com/author/abhishek/) + +How to Save the Output of a Command to a File in Linux Terminal [Beginner’s Tip] +====== + +When you run a command or script in the Linux terminal, it prints the output on the screen for your immediate viewing. + +There will be times when you need to save the output to a file for future references. Now, [you can surely copy and paste in Linux terminal][1] but there are better ways to save the output of a shell script or command in Linux command line. Let me show them to you. + +### Method 1: Use redirection to save command output to file in Linux + +You can [use redirection in Linux for this purpose][2]. With redirection operator, instead of showing the output on the screen, it goes to the provided file. + + * The > redirects the command output to a file replacing any existing content on the file. + * The >> redirects adds the command output at the end of the existing content (if any) of the file. + + + +Use the STDOUT redirection operator > for redirecting the output to a file like this: + +``` +command > file.txt +``` + +If the file.txt doesn’t exist, it will be created automatically. If you use the > redirect again with the same file, the file content is replaced by the new output. + +The example below demonstrates it better. It first saves the output of _ls -l_ command. And then later, it replaces the content of the file with the output of _ls *.c_ command. + +![Redirecting command output to file][3] + +If you don’t want to lose the content of the existing file while saving the output of a script or command, use the redirection operation in append mode with >>. + +``` +command >> file.txt +``` + +This example demonstrates it better: + +![Redirecting command output to file in append mode][4] + +Even here if the file doesn’t exist, it is created automatically. + +Bonus Tip: Save Linux command output as well as error to a file + +If your Linux command returns an error, it doesn’t get saved in the file. You can save both the command output and command error in the same file using 2>&1 like this: + +**command > file.txt 2>&1** + +Basically, 0 stands for standard input, 1 for standard output and 2 for standard error. Here, you are redirecting (>) standard error (2) to same address (&) as standard output (1). + +### Method 2: Use tee command to display the output and save it to a file as well + +By the way, did you notice that when you send the command output to a file, you cannot see it anymore on the display? The [tee command in Linux][5] solves this problem for you. + +Like a tee pipe that sends water stream into two directions, the tee command send the output to the display as well as to a file (or as input to another command). You can use it like this: + +``` +command | tee file.txt +``` + +Again, the file will be created automatically, if it doesn’t exist already. + +You may also use the tee command in append mode with option -a in this manner: + +``` +command | tee -a file.txt +``` + +Let me demonstrate it with some easy to follow examples: + +![][6] + +I have used simple Linux commands in my examples. But rest assured, you can use these methods to save the output of bash scripts as well. + +### Note: Avoid pipe pitfall while saving command output to file + +You probably are familiar with pipe redirection. You may use it to combine Linux commands but you cannot pipe the output to a file. It will result in error that filename command not found: + +![][7] + +This is because pipe redirects the output of one command to input of another command. And in this case, you give it a file name while it was expecting a command. + +If you are new to Linux command line, I hope this quick tutorial added to your Linux knowledge a bit. [I/O redirection][8] is an essential concept that one should be aware of. + +As always, questions and suggestions are always welcome. + +-------------------------------------------------------------------------------- + +via: https://itsfoss.com/save-command-output-to-file-linux/ + +作者：[Abhishek Prakash][a] +选题：[lujun9972][b] +译者：[译者ID](https://github.com/译者ID) +校对：[校对者ID](https://github.com/校对者ID) + +本文由 [LCTT](https://github.com/LCTT/TranslateProject) 原创编译，[Linux中国](https://linux.cn/) 荣誉推出 + +[a]: https://itsfoss.com/author/abhishek/ +[b]: https://github.com/lujun9972 +[1]: https://itsfoss.com/copy-paste-linux-terminal/ +[2]: https://linuxhandbook.com/redirection-linux/ +[3]: https://i1.wp.com/itsfoss.com/wp-content/uploads/2020/11/redirecting_command_output_to_file_in_linux.png?resize=741%2C456&ssl=1 +[4]: https://i2.wp.com/itsfoss.com/wp-content/uploads/2020/11/redirecting_command_output_to_file.png?resize=741%2C494&ssl=1 +[5]: https://linuxhandbook.com/tee-command/ +[6]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2020/11/display-and-save-linux-command-output.png?resize=741%2C494&ssl=1 +[7]: https://i0.wp.com/itsfoss.com/wp-content/uploads/2020/11/pipe-output-to-file-linux.png?resize=687%2C266&ssl=1 +[8]: https://tldp.org/LDP/abs/html/io-redirection.html#FTN.AEN17894