read is a command found on Unix and Unix-like operating systems such as Linux. It reads a line of input from standard input or a file passed as an argument to its -u flag, and assigns it to a variable. In Unix shells, like Bash, it is present as a shell built in function, and not as a separate executable file.
What is read command?
The read command reads one line from standard input and assigns the values of each field in the input line to a shell variable using the characters in the IFS (Internal Field Separator) variable as separators.
What is use of read command in Linux?
The Linux read command is used to read the contents of a line into a variable. This is a built-in command for Linux systems. … It is used to split the words that are tied to the shell variable. Primarily, it is used to take user input but can be used to implement functions while taking input.
What is read command in shell script?
read command in Linux system is used to read from a file descriptor. Basically, this command read up the total number of bytes from the specified file descriptor into the buffer. If the number or count is zero then this command may detect the errors. But on success, it returns the number of bytes read.
What is read in bash?
read is a bash built-in command that reads a line from the standard input (or from the file descriptor) and split the line into words. The first word is assigned to the first name, the second one to the second name, and so on. The general syntax of the read built-in takes the following form: read [options] [name…]
How do I run a shell script?
Steps to write and execute a script
- Open the terminal. Go to the directory where you want to create your script.
- Create a file with . sh extension.
- Write the script in the file using an editor.
- Make the script executable with command chmod +x <fileName>.
- Run the script using ./<fileName>.
What is read P?
read is a bash built-in (not a POSIX shell command) that reads from standard input. The -p option makes it read as a prompt, meaning it doesn’t add a trailing newline before trying to read input.
What is the purpose of in Unix?
Unix is an operating system. It supports multitasking and multi-user functionality. Unix is most widely used in all forms of computing systems such as desktop, laptop, and servers. On Unix, there is a Graphical user interface similar to windows that support easy navigation and support environment.
How do I use Linux?
- pwd — When you first open the terminal, you are in the home directory of your user. …
- ls — Use the “ls” command to know what files are in the directory you are in. …
- cd — Use the “cd” command to go to a directory. …
- mkdir & rmdir — Use the mkdir command when you need to create a folder or a directory.
How do you read a file in Linux?
From the Linux terminal, you must have some exposures to the Linux basic commands. There are some commands such as cat, ls, that are used to read files from the terminal.
Open the file using tail command.
- Open File Using cat Command. …
- Open File Using less Command. …
- Open File Using more Command. …
- Open File Using nl Command.
How do I read a bash file?
How to Read a File Line By Line in Bash. The input file ( $input ) is the name of the file you need use by the read command. The read command reads the file line by line, assigning each line to the $line bash shell variable. Once all lines are read from the file the bash while loop will stop.
Why we use read in shell script?
Read is a bash builtin command that reads the contents of a line into a variable. It allows for word splitting that is tied to the special shell variable IFS. It is primarily used for catching user input but can be used to implement functions taking input from standard input.
How do I read a bash script?
To read the Bash user input, we use the built-in Bash command called read. It takes input from the user and assigns it to the variable. It reads only a single line from the Bash shell.
- # using read command without any variable.
- echo “Enter name : “
- echo “Name : $REPLY”