How do you store command output in variable in shell?

How do you store command output in variable in shell?

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 do you declare an array in Unix shell script?

How to Declare Array in Shell Scripting?

1. Indirect Declaration. In Indirect declaration, We assigned a value in a particular index of Array Variable. No need to first declare.
2. Explicit Declaration. In Explicit Declaration, First We declare array then assigned the values. declare -a ARRAYNAME.
3. Compound Assignment.

How do I sort an array in Linux?

“${array[*]}” <<< sort. sorted=($(…))…

1. Open an inline function {…} to get a fresh set of positional arguments (e.g. $1 , $2 , etc).
2. Copy the array to the positional arguments.
3. Print each positional argument (e.g. printf ‘%s\n’ “$@” will print each positional argument on its own line.
4. Then sort does its thing.

When to use arrays or loops in a shell?

Using arrays or loops in shells is often signs of bad coding practice. A shell is a tool to run other commands. awk is the typical command to do complicated tasks with fields in text records. You want to call awk once for your task, not a loop where you’re going to run hundreds of commands.

How to assign a command to an array in Bash?

This resulted in a bunch of lines with line numbers in which the search term was found. What’s the easiest way to assign them to a bash array? If I simply assign them to a variable they become a space-separated string. To assign the output of a command to an array, you need to use a command substitution inside of an array assignment.

Why is my output not stored in an array?

Using bash and processing piped output with a while read leaves any variables set or created inside of the loop unchanged or undefined following the execution of the while. The bad substitution is probably the result of the array not being defined, though when I execute your code under bash it fails silently.

Why do I need to redirect output to an array?

The bad substitution is probably the result of the array not being defined, though when I execute your code under bash it fails silently. If you really must do the processing in script then you’re probably going to need to redirect the output to a tmp file and read the lines into an array after the fact.