Redirect of stdout and stderr work on linux, osx and unix. Because of this is not under `Linux things...` section! :)

# To suppress error:

# To suppress out:./somescript.sh 1> /dev/null

# To suppress both:./somescript.sh 2>&1 > /dev/null

In Bash, you can redirect error output (stderr) into a variable using a process substitution or a temporary 
file. Here are a few methods to achieve this:
 
### Method 1: Using Process Substitution
 
You can use process substitution to capture the error output into a variable:
 
```bash
ERROUT=$(ls -l somefile.txt 2>&1 >/dev/null)
```
 
However, this captures both stdout and stderr. If you want to capture only stderr, you can use:
 
```bash
ERROUT=$(ls -l somefile.txt 2>&1 >/dev/null)
```
 
But this is not very clean. A better approach is to use a temporary file or a named pipe.
 
### Method 2: Using a Temporary File
 
Create a temporary file to capture the error output, then read it into a variable:
 
```bash
# Create a temporary file
TEMP_FILE=$(mktemp)
 
# Redirect stderr to the temporary file
ls -l somefile.txt 2> "$TEMP_FILE"
 
# Read the error output into the variable
ERROUT=$(cat "$TEMP_FILE")
 
# Remove the temporary file
rm "$TEMP_FILE"
 
# Print the error output
echo "Error output: $ERROUT"
```
 
### Method 3: Using a Named Pipe (FIFO)
 
You can use a named pipe to capture the error output:
 
```bash
# Create a named pipe
PIPE=$(mktemp -u)
mkfifo "$PIPE"
 
# Redirect stderr to the named pipe in the background
ls -l somefile.txt 2> "$PIPE" &
 
# Read the error output from the named pipe into the variable
ERROUT=$(cat "$PIPE")
 
# Remove the named pipe
rm "$PIPE"
 
# Print the error output
echo "Error output: $ERROUT"
```
 
### Method 4: Using a Function
 
You can create a function to capture the error output:
 
```bash
capture_error() {
    local cmd="$1"
    local output
    output=$(eval "$cmd" 2>&1 >/dev/null)
    echo "$output"
}
 
ERROUT=$(capture_error "ls -l somefile.txt")
 
echo "Error output: $ERROUT"
```
 
### Method 5: Using `exec` to Redirect stderr
 
You can use `exec` to redirect stderr to a file descriptor, then read it into a variable:
 
```bash
# Redirect stderr to file descriptor 3
exec 3>&2
ls -l somefile.txt 2>&3 | while read -r line; do
    ERROUT+="$line"
done
 
# Reset stderr
exec 3>&-
 
echo "Error output: $ERROUT"
```
 
### Best Approach
 
The most straightforward and commonly used method is to use a temporary file or a named pipe. Here's a clean 
example using a temporary file:
 
```bash
# Create a temporary file
TEMP_FILE=$(mktemp)
 
# Redirect stderr to the temporary file
ls -l somefile.txt 2> "$TEMP_FILE"
 
# Read the error output into the variable
ERROUT=$(cat "$TEMP_FILE")
 
# Remove the temporary file
rm "$TEMP_FILE"
 
# Print the error output
echo "Error output: $ERROUT"
```
 
### Example with a Script
 
If you want to capture the error output of a script, you can do:
 
```bash
# Create a temporary file
TEMP_FILE=$(mktemp)
 
# Run the script and redirect stderr to the temporary file
./yourscript.sh 2> "$TEMP_FILE"
 
# Read the error output into the variable
ERROUT=$(cat "$TEMP_FILE")
 
# Remove the temporary file
rm "$TEMP_FILE"
 
# Print the error output
echo "Error output: $ERROUT"
```
 
### Summary
 
- **Process Substitution**: Simple but captures both stdout and stderr.
- **Temporary File**: Clean and straightforward.
- **Named Pipe**: Useful for more complex scenarios.
- **Function**: Reusable and flexible.
- **exec**: Advanced but powerful.
 
Choose the method that best fits your needs. The temporary file method is often the most straightforward and 
reliable for capturing error output into a variable.