Process File Redirect To Another

When processing files' content for transformation or analysis. Exact Command syntax, copyable example, output expectations, and common mistakes.

Terminal

<command> < <path/to/file.txt> > <path/to/file2.txt>

<command> < <path/to/file.txt> > <path/to/file2.txt>

#!/bin/bash

# Process File Redirect To Another
{{command}} < {{path/to/file.txt}} > {{path/to/file2.txt}}

When To Use

Use this when a command expects stdin and you want to provide it from a file.

Pro Tip

Inspect the redirected input file before running so the command receives the exact content you expect.

Command Result

What happens when it runs

Shell behavior

Primary Effect

Reads from file. 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 redirected input file does not exist

Solution: Create the input file or fix the path before running the command.

The input file contents are malformed

Solution: Validate the redirected file contents before execution.

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.
<path/to/file2.txt>: Input Files; The file path or paths supplied to this command.
<: Input Redirection; Reads standard input from the source file before the command executes.
<path/to/file.txt>: Input Source; The file or token that provides shell input for this command.

How To Run

Step 1
Prepare the file path with the expected input content before running the command.
Step 2
Run the command and validate the resulting stdout or downstream side effect.

Alternative Approaches

Alternative filesystem tools for the same job.