Here Document To Stdin

During configuration scripts that require multiline parameters. Exact Command syntax, copyable example, output expectations, and common mistakes.

Terminal

<command> << <EOF> <Enter> <multiline_text> <Enter> <EOF>

<command> << <EOF> <Enter> <multiline_text> <Enter> <EOF>

#!/bin/bash

# Here Document To Stdin
{{command}} << {{EOF}} <Enter> {{multiline_text}} <Enter> {{EOF}}

When To Use

Use this when inline multiline shell input is clearer than creating a separate file first.

Pro Tip

Keep the heredoc terminator on its own line so the shell closes the block where you expect.

Command Result

What happens when it runs

Shell behavior

Primary Effect

Uses shell redirection. The shell provides input from the source file before Command runs.

Terminal Expectation

The shell may not print a visible result. Validate the affected input or output path after the command runs.

Troubleshooting

The heredoc terminator does not match

Solution: Use the same marker at both the start and end of the heredoc block.

Indentation changes the heredoc content

Solution: Check whether the command uses << or <<- before indenting lines.

Command Breakdown

<command>: Base Command; The executable that performs this operation. Here it runs Command before the shell applies any redirect operators.
<command>: command; The value supplied for command.
<multiline_text>: multiline text; The value supplied for multiline text.
<<: Shell Redirection; Changes how the shell routes input or output for this command.
<EOF>: Input Source; The file or token that provides shell input for this command.

How To Run

Step 1
Enter the multiline block exactly as required by the command after the heredoc opener.
Step 2
Terminate the heredoc with EOF and then verify the resulting file or stdout.

Alternative Approaches

Alternative tools that share the "process-text" operation intent.