When working with multiple files in Linux, the cat command is our go-to tool for quick file concatenation. However, its default behavior of merging files without visual separation can make it difficult to distinguish where one file ends and another begins.

For a pure Bash solution that doesn't require installing additional packages:

for f in *; do cat "$f"; printf 'XXXXXXXXXXXX\\n'; done

Or using echo:

for f in *; do cat "$f"; echo "XXXXXXXXXXXX"; done

For better readability and customization:

# With dynamic separators showing filenames
for file in *; do
    echo "===== Contents of $file ====="
    cat "$file"
    echo ""
done

Using awk for more control:

awk 'FNR==1{if(NR>1) print "XXXXXXXXXXXX";} {print;}' *

Add this to your .bashrc for a persistent solution:

function catsep() {
    for f in "$@"; do
        cat "$f"
        echo "XXXXXXXXXXXX"
    done
}

Now you can simply run:

catsep *

The bat command (a cat alternative) provides built-in file separation:

bat --style=header,grid *

---

When working with multiple files in Linux, the cat command's default behavior concatenates files without any visual separation between them. This can make it difficult to distinguish where one file ends and another begins, especially when dealing with similar content.

This situation frequently occurs when:

• Reviewing logs from multiple services
• Comparing configuration files
• Examining output from related processes
• Debugging scripts with multiple source files

The most straightforward solution uses a for loop with echo:

for f in *; do cat "$f"; echo -e "\nXXXXXXXXXXXX\n"; done

This will:

1. Process each file in the current directory
2. Display its contents
3. Add a separator line after each file

For more control over the output:

Include Filename Headers

for f in *; do echo -e "\n=== $f ===\n"; cat "$f"; done

Colorized Separators

for f in *; do cat "$f"; echo -e "\n\033[1;31m==========\033[0m\n"; done

Using awk for Better Formatting

awk 'FNR==1 && NR!=1 {print "XXXXXXXXXXXX"} 1' *

This awk command:

• Prints the separator before each new file (except the first)
• Preserves all original file contents
• Handles large files efficiently

For frequent use, create a function in your ~/.bashrc:

function catsep() {
  for f in "$@"; do
    [ -f "$f" ] && cat "$f" && echo -e "\nXXXXXXXXXXXX\n"
  done
}

Usage:

catsep file1 file2 file3

For very large directories or files:

• The awk solution is generally fastest
• Shell loops have more overhead
• Consider find -exec for recursive operations