Bash Pipe |

Basic Usage

• Piping Between Commands:

  command1 | command2
  

  Output of command1 is used as input for command2.

Combining Multiple Commands

• Sequential Commands:

  command1 | command2 | command3
  

  Output of command1 is passed to command2, and its output is passed to command3.

Filtering and Processing Text

• Grep:

  command | grep 'pattern'
  

  Filters the output of command for lines containing ‘pattern’.

• Sort:

  command | sort
  

  Sorts the output of command.

• Awk:

  command | awk '{print $1}'
  

  Processes the output of command using awk (e.g., prints the first column).

• Sed:

  command | sed 's/old/new/'
  

  Processes the output of command using sed (e.g., replaces ‘old’ with ‘new’).

Redirection and File Operations

• Tee:

  command | tee file.txt
  

  The output of command is both displayed and written to file.txt.

Combining Text Streams

• Paste:

  command1 | paste - command2
  

  Combines the output of command1 and command2 side by side.

Networking and Data Transfer

• Curl and Processing:

  curl -s http://example.com | grep 'title'
  

  Fetches data from a URL and filters it.

• SSH and Remote Commands:

  ssh user@host 'cat file' | grep 'pattern'
  

  Executes a command on a remote machine and processes the output locally.

Advanced Usage

• Process Substitution:

  diff <(command1) <(command2)
  

  Compares the output of two commands using diff.

• Xargs for Batch Processing:

  command1 | xargs -n1 command2
  

  Uses the output of command1 as arguments for command2, one at a time.

Debugging and Analysis

• Pipe Viewer (pv):

  command1 | pv | command2
  

  Monitors the progress of data through a pipe between two commands.

Chains with Conditional Execution

• AND and OR Lists:

  command1 && command2 | command3
  command1 || command2 | command3
  

  Executes command2 only if command1 succeeds/fails, then pipes to command3.