strace Command in Linux

Syntax of strace Command in Linux

The basic syntax of the strace command in Linux is as follows:

Where:

• option: These are optional flags that modify the behavior of strace.
• command: This is the command or program that you want to trace.

Options in strace Command in Linux

1. -c: This option makes strace print a summary of system calls instead of a step-by-step trace.

   For example -

   Output:

   The '-c' option triggers strace to provide statistical data about the system calls.

2. -o: The '-o' option followed by a file name directs strace to write the output into a file instead of standard output.

   For example -

   Output:

   This option is useful when tracing a process that generates a lot of output or when the output needs to be analyzed at a later stage.

3. -p: The '-p' option is followed by a process ID (PID). This allows strace to attach to a running process and trace its system calls.

   For example -

   Output:

   This is particularly useful when you need to debug a running process or program.

Example Usages

• Basic usage of strace:

  Output:

  Explanation: This is the simplest way to use strace command in Linux to view the system calls made by a command.

• Tracing specific system calls:

  Output:

  Explanation: With the '-e' option, you can specify the system calls you are interested in. This helps to filter out the noise when tracing a process.

Advanced Use Cases of strace Command in Linux

• Tracing a running process:

  Output:

  Explanation: With the '-p' option, strace becomes a powerful tool to trace a running process. This is especially useful in debugging scenarios.

• Trace child processes:

  Output:

  Explanation: The '-f' option allows strace to follow child processes spawned by the main process. This gives a comprehensive view of the entire process tree.

• Limit strace output to errors:

  Output:

  Explanation: This is useful when you're interested in knowing the system calls which failed during the execution of a program.