Redirections - 3lsy/minishell GitHub Wiki

Redirections

In one single command it is only possible to have from ZERO to N redirections.

Redirection Symbol	Description
`<`	Redirects input.	Needs the file created.
`>`	Redirects output.	Creates the file.
`<<`	Reads input until a line containing the delimiter is seen.	Needs the file created.
`>>`	Redirects output in append mode.	Creates the file.

Multiple redirections

If a simple command has multiple redirections, extract blindly EVERY redirection with it's respective filename. The rest is your command.

Example

$ > hello this thing >> another is confusing << yes
# This will result in
## Redirections: (redirection, filename)
[(>, hello), (>>, another), (<<, yes)]
## Command
[this, thing, is, confusing]

! To confirm If there are multiple redirections, only the last one will redirects it seems.

Examples

<

# Example using 'cat' command to read input from a file
cat < input_file.txt

# Example using < without a command and at the beginning of the line (only when file exists)
< input_file.txt

>

# Example using 'echo' command to write output to a file
echo "Hello, World!" > output_file.txt

# Example using > without a command and at the beginning of the line
> output_file.txt
ls
output_file.txt

<<

# Example using 'cat' command to read input until the delimiter 'EOF' is encountered
cat << EOF
This is line 1.
This is line 2.
EOF

# Example using << without a command and at the beginning of the line
<< EOF
This is line 1.
This is line 2.
EOF

>>

# Example using 'echo' command to append output to a file
echo "This will be appended." >> output_file.txt

# Example using >> without a command and at the beginning of the line
>> output_file.txt
ls
output_file.txt

< >

# Redirect input from input_file.txt, and redirect output to output_file.txt
cat < input_file.txt > output_file.txt

< >>

# Redirect input from input_file.txt, and append output to output_file.txt
cat < input_file.txt >> output_file.txt

<< >

# Read input from a here document and write output to output_file.txt
cat << EOF > output_file.txt
This is line 1.
This is line 2.
EOF

>> <<

# Append input from a here document to output_file.txt
cat >> output_file.txt << EOF
This is line 1.
This is line 2.
EOF