What is the purpose of process substitution (<(...) )in Bash?

Process substitution in Bash, denoted by <(...), allows you to treat the output of a command as if it were a file. This is useful when you want to pass the output of a command to another command that expects a filename as an argument.

Purpose and Benefits

1. Input Redirection: It enables you to use the output of a command as input for another command without creating temporary files.

2. Efficiency: It avoids the overhead of writing to and reading from temporary files, making scripts more efficient.

3. Simplicity: It simplifies complex command pipelines by allowing you to use the output of multiple commands directly.

Example

Here’s an example of using process substitution:

diff <(sort file1.txt) <(sort file2.txt)

In this example:

• sort file1.txt and sort file2.txt are executed in the background.
• The output of each sort command is treated as a file.
• diff compares the sorted outputs without needing to create intermediate files.

Conclusion

Process substitution is a powerful feature in Bash that enhances the flexibility and efficiency of command-line operations, especially when dealing with multiple commands and their outputs.