Linux scripting create file

How to Create a File in Shell Script in Linux: A Comprehensive Guide

Learn how to create a file in shell script in Linux using various commands and techniques. This comprehensive guide provides helpful tips and tricks for creating different types of files.

• Using Cat Command to Create Empty Text File
• Using Cat Command to Create a File with Content
• Shell Scripting Tutorial-4: Create Files & Directories
• Using Touch Command to Create a File
• Creating a Shell Script
• Using BASH To Create Files and Folders
• Creating an Empty File using mkdir and touch command
• Four Ways to Write a File while Bash Scripting
• Creating a New Empty File using echo command
• How do I create a file in a directory in shell script?
• How do I create a script file?
• How do I create a .sh file in Linux?
• What is the command to create a file?

Creating files is a fundamental part of shell scripting in linux . Whether you are a beginner or an experienced user, knowing how to create a file is crucial if you want to work with the Linux operating system. In this blog post, we will provide a comprehensive guide on how to create a file in shell script in Linux, along with some helpful tips and tricks.

Using Cat Command to Create Empty Text File

The cat command is a common way to create an empty text file in Linux. The command to create an empty text file named foo is:

This command creates an empty text file named foo in the current directory. The “>” symbol is used to redirect the standard output to a file. When you run this command, the cat command opens a new file called “foo” and waits for input. Type nothing and press “Enter” to create an empty file.

Using Cat Command to Create a File with Content

The cat command can also be used to create a file with some content in Linux. To create a file with some content, use the cat command followed by file name and content, and press CTRL + D. The command looks like this:

$ cat > foo.txt Hello, World! ^D 

This command creates a file named “foo.txt” with the text “Hello, World!” in the current directory. The “^D” symbol means pressing “CTRL + D” to end the input. You can also use the cat command with the “

Shell Scripting Tutorial-4: Create Files & Directories

Official Facebook Page: http://www.facebook.com/TheBadTutorialsIn this tutorial you’ll learn to
Duration: 5:27

Using Touch Command to Create a File

The touch command is another way to create a new file in Linux. To create a new file using the touch command, use the command:

This command creates a new file with the specified filename in the current directory. If the file already exists, the touch command updates the timestamp of the file. The touch command is useful when you need to create an empty file quickly.

Creating a Shell Script

To create a shell script in Linux, use a text editor to create a file with a .sh extension. Then, start the file with “#!/bin/bash” to indicate that the file should be executed using the bash shell. The command to create a new shell script file with the specified name and extension in the current directory looks like this:

This command opens a new file called “script.sh” in nano editor. You can replace “nano” with your favorite text editor. Add “#!/bin/bash” as the first line of the file to specify that the script should be executed using the bash shell. Then, add your commands to the script.

Using BASH To Create Files and Folders

Two new commands:mkdir [filename] will create a directory called [filename].touch [filename
Duration: 6:43

Creating an Empty File using mkdir and touch command

Another way to create an empty file is by using the mkdir and touch commands. First, create a new directory using the mkdir command:

This command creates a new directory with the specified name in the current directory. Then, navigate to the directory and create an empty file using the touch command:

$ cd dirname $ touch filename 

This command creates a new empty file with the specified name in the specified directory. This method is useful when you need to create a file in a specific directory.

Four Ways to Write a File while Bash Scripting

There are four ways to write any file while bash scripting : using directional operators, using tee command, using printf, and using heredoc format.

Using Directional Operators

You can use directional operators to write the output of a command to a file. The “>” operator redirects the standard output to a file and overwrites the file if it already exists. The “>>” operator appends the output to a file if it already exists. For example:

$ echo "Hello, World!" > output.txt 

This command creates a file called “output.txt” with the text “Hello, World!”. If the file already exists, the “>” operator overwrites the file.

Using Tee Command

The tee command is another way to write the output of a command to a file. The tee command reads the standard input and writes it to both standard output and a file. The command looks like this:

$ echo "Hello, World!" | tee output.txt 

This command writes the text “Hello, World!” to both standard output and a file called “output.txt”.

Using Printf

You can use the printf command to write formatted output to a file. The command looks like this:

$ printf "Hello, %s!\n" "World" > output.txt 

This command writes the formatted string “Hello, World!” to a file called “output.txt”. The “%s” symbol is used to specify a string, and the “\n” symbol is used to add a newline character.

Using Heredoc Format

The heredoc format is a way to write multiple lines of text to a file. The command looks like this:

$ cat output.txt Hello, World! This is a test. EOF 

This command writes the text “Hello, World!” and “This is a test.” to a file called “output.txt”. The “

Creating a New Empty File using echo command

To create a new empty file in a bash script, use the command:

This command creates a new empty file with the specified name in the current directory.

creating files in shell script in Linux is a common task that can be accomplished using various commands and techniques. The cat, touch, mkdir, and echo commands can be used to create different types of files in linux . Understanding the advantages, disadvantages, and best practices for creating shell scripts can help improve file creation efficiency and effectiveness. Remember to choose the method that suits your needs and always test your scripts before using them in production.

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Creating files with some content with shell script

I need to configure a server with a few files and I want to do it programmatically. I need to create files say /home/a.config, /var/spool/b.config, /etc/c.config Files above have some contents (multi lines). I want to create ONE shell script which can create all three file with multiple lines (around 10). I would like to know the how can I use CAT command to do that. (inside shell script). I am looking something like this

echo " going to create /home/a.config" cat "HOW CAN I HAVE MULTIPLE LINES HERE?? " > /home/a.config 

5 Answers 5

cat filename first line second line third line EOF 

You can place several of these in the same script.

@Nagev: If you don’t want any parameter expansion, command substitution, and arithmetic expansion in the here document you can quote the beginning delimiter ‘EOF’ instead of having to escape each individual dollar sign.

@JúlioFalbo: If you don’t quote the here doc delimiter (e.g. EOF ) then parameters (variables) in the text will be expanded.

file="/tmp/test.txt" echo "Adding first line" > $file echo "Adding first line replaced" > $file echo "Appending second line " >> $file echo "Appending third line" >> $file cat $file 

> to add/replace the content ( here actual content got replaced by the 2nd line)
>> to append

Result
Adding first line replaced
Appending second line
Appending third line

#!/bin/bash var="your text" echo "simply put, just so: $var" > a.config 

For further info, see Input/Output part of abs.
Hope, this helps.

If you’ve got variables like $1 or $HOMEDIR in your text then these normally get evaluated and substituted with actual values. If you want to prevent these from getting substituted then you need to quote the opening limit string (EOF in example below) with single quote ‘EOF’ , double quote «EOF» or precede it with backslash \EOF

Closing limit string stays as is. EOF

This is especially useful if you are writing shell scripts to a file.

cat /etc/rc.d/init.d/startup case $1 in start) start ;; stop) stop ;; restart) stop start ;; status) pid=$(tomcat_pid) if [ -n "$pid" ] then echo "Tomcat is running with pid: $pid" else echo "Tomcat is not running" fi ;; esac EOF 

Refer Example 19.7 Parameter Substitution Turned off in Here Documents

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How do I create a new empty file in a bash script?

I’m running some third-party Perl script written such that it requires an output file for the output flag, -o . Unfortunately, the script appears to require an actual file, that is, users must create an empty file filename.txt with 0 bytes and then input this empty file on the script command line

perl script1.pl -o filename.txt 

Question: How would I create an empty file within a bash script? If one simply tries perl script1.pl -o filename.txt , the script gives an error that the file doesn’t exist.

5 Answers 5

Use touch command. touch filename.txt .

Actually I tried touch and «echo -n > file» inside my bash script but I get an error when I execute the script: «No such file or directory» on that line. Can someone help please?

Use the null command ( : ) redirect ( > filename ) trick ( :> ), as this will truncate to zero or create the named file.

$ echo foo > filea $ :> filea $ wc -c filea 0 filea $ rm filea $ :> filea $ wc -c filea 0 filea 

(This will fail if the shell sets a NOCLOBBER option.)

Just > filename.txt would do, no need for the : . Or >> filename.txt if we don’t want to trash it if it does happen to exist.

@ilkkachu although the question does specify Bash, using : does make the script more likely to accomplish its task with other shells e.g. Zsh.

You could always use perl, too.

$ stat filename.txt stat: cannot stat 'filename.txt': No such file or directory $ perl -e 'open($fh,">","filename.txt") or die $!;close($fh)' $ stat filename.txt File: 'filename.txt' Size: 0 Blocks: 0 IO Block: 4096 regular empty file Device: 801h/2049d Inode: 280728 Links: 1 Access: (0664/-rw-rw-r--) Uid: ( 1000/ xieerqi) Gid: ( 1000/ xieerqi) Access: 2017-02-08 13:51:01.479121995 -0700 Modify: 2017-02-08 13:51:01.479121995 -0700 Change: 2017-02-08 13:51:01.479121995 -0700 Birth: - 

dd can be used to create an empty file as follows:

dd if=/dev/null of=filename.txt count=0 

One case where dd is more useful than the other approaches is creating an EFI variable (PK) through the efivars filesystem ( /sys/firmware/efi/efivars ).

One some platforms and Linux distributions, the file is created with the » immutible » attribute set (shows up as the » i » flag with » lasattr «). So, any subsequent operations on the file fail.

For example, touch not only creates the file, but sets the time stamp on the file. Similarly, piping to the file with > not only creates the file, but performs additional operations that fail. The dd command does not appear to fail the same way.

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