expr:tldr:327a4
expr: Get the substring of a string with a specific length.
$ expr substr "${string}" ${from} ${length}
try on your machine
The expr substr command is used to extract a substring from a given string. Here is the breakdown of the syntax:
"${string}": This represents the variable or the string from which the substring will be extracted. It is enclosed in double quotes to handle cases where the string contains spaces or special characters.${from}: This specifies the starting position (index) from where the extraction should begin. It is an integer value.${length}: This defines the length or number of characters to be extracted from the given string starting from the${from}position. It is also an integer value.
When the expr substr command is executed with the provided arguments, it will return the extracted substring based on the given starting position and length.
For example, let's say we have the following command:
string="Hello World"
expr substr "${string}" 7 5
In this case, the starting position is 7 and the length is 5. So, the command will return the substring "World" from the given string "Hello World".
This explanation was created by an AI. In most cases those are correct. But please always be careful and
never run a command you are not sure if it is safe.