BASH command output to the variable

Different types of bash commands need to be run from the terminal based on the user's requirements. When the user runs any command from the terminal then it shows the output if no error exists otherwise it shows the error message.

1. How do you put the output of a command into a variable bash?
2. How do you redirect output of a command to a variable?
3. How assign grep output to variable in shell script?
4. How do you execute a command in a variable in shell script?
5. What is the output of who command?
6. How do you set a variable in bash?
7. How do you assign a cat to a variable?
8. How do you set a variable in UNIX?
9. How do I use Xargs command?
10. How do you grep the output of a command in shell script?
11. What is the output of grep?
12. How check grep output is empty?

How do you put the output of a command into a variable bash?

Bash Assign Output of Shell Command To And Store To a Variable

1. var=$(command-name-here) var=$(command-name-here arg1) var=$(/path/to/command) var=$(/path/to/command arg1 arg2) ...
2. var=`command-name-here` var=`command-name-here arg1` var=`/path/to/command` var=`/path/to/command arg1 arg2`

How do you redirect output of a command to a variable?

To store the output of a command in a variable, you can use the shell command substitution feature in the forms below: variable_name=$(command) variable_name=$(command [option ...] arg1 arg2 ...) OR variable_name='command' variable_name='command [option ...] arg1 arg2 ...'

How assign grep output to variable in shell script?

The syntax is:

1. VAR=`command-name` VAR="`grep word /path/to/file`" ## or ## VAR=$(command-name) VAR="$(grep word /path/to/file)" ...
2. echo "Today is $(date)" ## or ## echo "Today is `date`" ...
3. todays=$(date) ...
4. echo "$todays" ...
5. myuser="$(grep '^vivek' /etc/passwd)" echo "$myuser"

How do you execute a command in a variable in shell script?

Here, the first line of the script i.e. “#!/bin/bash” shows that this file is in fact a Bash file. Then we have created a variable named “test” and have assigned it the value “$(echo “Hi there!”)”. Whenever you want to store the command in a variable, you have to type that command preceded by a “$” symbol.

What is the output of who command?

The basic syntax for using who command is as follows. 1. If you run who command without any arguments, it will display account information (user login name, user's terminal, time of login as well as the host the user is logged in from) on your system similar to the one shown in the following output.

How do you set a variable in bash?

To create a variable, you just provide a name and value for it. Your variable names should be descriptive and remind you of the value they hold. A variable name cannot start with a number, nor can it contain spaces. It can, however, start with an underscore.

How do you assign a cat to a variable?

Using a variable inside a file to cat another.

Create a shell variable called "f_name", assign it the string "file_1". Use the cat command and the variable "f_name" to display the contents of the file...

How do you set a variable in UNIX?

If what you want is for the variable to be available to every session, instead of just the current one, you will need to set it in your shell run control. Then add the set line or the setenv line shown above to automatically set the variable or environment variable for every session of csh.

How do I use Xargs command?

10 Xargs Command Examples in Linux / UNIX

1. Xargs Basic Example. ...
2. Specify Delimiter Using -d option. ...
3. Limit Output Per Line Using -n Option. ...
4. Prompt User Before Execution using -p option. ...
5. Avoid Default /bin/echo for Blank Input Using -r Option. ...
6. Print the Command Along with Output Using -t Option. ...
7. Combine Xargs with Find Command.

How do you grep the output of a command in shell script?

This is fairly simple: OUTPUT=$(pfiles "$1" 2> /dev/null | grep peername) grep_return_code=$? if ! OUTPUT=$(pfiles "$1" 2> /dev/null | grep peername) then exit fi # the rest of the script ︙

What is the output of grep?

Displaying only the matched pattern : By default, grep displays the entire line which has the matched string. We can make the grep to display only the matched string by using the -o option. 6. Show line number while displaying the output using grep -n : To show the line number of file with the line matched.

How check grep output is empty?

The -q option is used here just to make grep quiet (don't output...) You haven't save the results of grep $address /etc/passwd in a variable. before putting it in the if statement and then testing the variable to see if it is empty.