fish-shell/doc_src/read.txt

\section read read - read line of input into variables

\subsection read-synopsis Synopsis
<tt>read [OPTIONS] [VARIABLES...]</tt>

\subsection read-description Description

The <tt>read</tt> builtin causes fish to read one line from standard
input and store the result in one or more environment variables. 

- <tt>-c CMD</tt> or <tt>--command=CMD</tt> specifies that the initial string in the interactive mode command buffer should be CMD.
- <tt>-e</tt> or <tt>--export</tt> specifies that the variables will be exported to subshells.
- <tt>-g</tt> or <tt>--global</tt> specifies that the variables will be made global.
- <tt>-p PROMPT_CMD</tt> or <tt>--prompt=PROMPT_CMD</tt> specifies that the output of the shell command PROMPT_CMD should be used as the prompt for the interactive mode prompt. The default prompt command is <tt>set_color green; echo read; set_color normal; echo "> "</tt>.
- <code>-u</code> or <code>--unexport</code> causes the specified environment not to be exported to child processes
- <code>-U</code> or <code>--universal</code> causes the specified environment variable to be made universal. If this option is supplied, the variable will be shared between all the current users fish instances on the current computer, and will be preserved across restarts of the shell.
- <code>-x</code> or <code>--export</code> causes the specified environment variable to be exported to child processes

Read starts by reading a single line of input from stdin, the line is
then tokenized using the <tt>IFS</tt> environment variable. Each variable
specified in <tt>VARIABLES</tt> is then assigned one tokenized string
element. If there are more tokens than variables, the complete
remainder is assigned to the last variable.

\subsection read-example Example

<tt>echo hello|read foo</tt>

Will cause the variable \$foo to be assigned the value hello.