How to create and write data into files in Linux

Java, Linux-Unix, Operating Systems
Comments

How to create and write data into files in Linux

This article explained how to create and write data into files in the Linux and Unix flavors. By using different types of commands we can create the files and we can write the data into files.

Create Empty Files

touch

using the touch command, we can create the empty file

touch /tmp/sample.txt

Create Files via vi editor command

Using the vi editor command-line tool, we can create empty or data files.

vi /tmp/sample.txt

Create and Writing data into files

Using the below command to create and write the data into a file.

Syntax
command > /tmp/sample.txt

Example
ls > /tmp/sample.txt

 

Append data into the file

Syntax
command >> /tmp/sample.txt

Example
ls >> /tmp/sample.txt

Sample data writing
echo "--------------" >> /tmp/sample.txt
echo "Domain information" >> /tmp/sample.txt
host www.narayanatutorial.com >> /tmp/sample.txt
echo "--------------" >> /tmp/sample.txt

Save the output of a command to a file

The tee command reads from standard input and writes to standard output and files.

The syntax is as follows for writing data into the file:

Syntax
command | tee /tmp/sample.txt

Example
ls | tee /tmp/sample.txt
date | tee /tmp/sample.txt

Append the data into the file

Syntax
command | tee -a /tmp/sample.txt

Example
ls | tee -a /tmp/sample.txt
date | tee -a /tmp/sample.txt

Here -a append the data into a file.

 

Comand Description Overwrite existing file?
command > sample.txt Save terminal output (standard output) to a file named sample.txt Yes
command >> sample.txt Append terminal output (standard output) to a file named sample.txt No
command Takes standard input from sample.txt file N/A
command 0 Takes standard input from sample.txt file N/A
command 1> sample.txt Puts standard output to sample.txt file Yes
command 1>> sample.txt Appends standard output to sample.txt No
command 2> sample.txt Puts standard error to sample.txt Yes
command 2>> sample.txt Appends standard error to sample.txt file No
command &> sample.txt Puts both standard error and output to sample.txt Yes
command > sample.txt 2>&1 {POSIX} Puts both standard error and output to file named sample.txt Yes
command &>> sample.txt Appends both standard error and output to file named sample.txt No
command >> sample.txt 2>&1 {POSIX} Appends both standard error and output to file called sample.txt No
command | tee sample.txt Puts standard output to sample.txt while displaying output on screen Yes
command | tee -a sample.txt Appends standard output to sample.txt while displaying output on screen No
command |& tee sample.txt Puts both standard output and error to sample.txt while displaying output on terminal Yes
command 2>&1 | tee sample.txt {POSIX} Puts both standard output and error to file named sample.txt while displaying output on terminal Yes
command |& tee -a sample.txt Append both standard output and error to file called sample.txt while displaying output on terminal No
command 2>&1 | tee -a sample.txt {POSIX} Append both standard output and error to file named sample.txt while displaying output on terminal No

 

Related Posts

Leave a Reply