Strace is a powerful command-line tool that can be used for tracing system calls and signals in Linux. It is an essential tool for system administrators, developers, and programmers to debug issues and optimize system performance. In this article, we will provide a complete guide to mastering the Strace command in Linux.
What is Strace?
Strace is a system call tracer that captures and displays the system calls made by a program or process. It can also display signals and other related information. Strace is a powerful tool for debugging issues in applications or for investigating system performance issues. Strace is often used in combination with other Linux tools, such as ltrace, gdb, and tcpdump.
Installing Strace
Strace is pre-installed on most Linux distributions. However, if it is not installed on your system, you can easily install it using your distribution’s package manager. For example, to install Strace on Ubuntu, use the following command:
sudo apt-get install strace
Basic Usage
To use Strace, simply prefix the command that you want to trace with the “strace” command. For example, to trace the “ls” command, use the following command:
strace ls
This command will display all the system calls made by the "ls" command. You can also use the "-p" option to trace a running process. For example, to trace the process with PID 1234, use the following command:
strace -p 1234
Filtering System Calls
By default, Strace will display all system calls made by a process. However, you can filter the output by using the "-e" option followed by a comma-separated list of system calls. For example, to display only the "open" and "read" system calls made by the "ls" command, use the following command:
strace -e open,read ls
This command will display only the "open" and "read" system calls made by the "ls" command.
Displaying Signal Information
Strace can also display information about signals received by a process. To display signal information, use the "-e" option followed by the signal name or number. For example, to display information about the "SIGINT" signal received by the "ls" command, use the following command:
strace -e signal=SIGINT ls
This command will display information about the "SIGINT" signal received by the "ls" command.
Displaying Timestamps
You can display timestamps for each system call by using the "-t" option. For example, to display timestamps for all system calls made by the "ls" command, use the following command:
strace -t ls
Redirecting Output
By default, Strace outputs to the terminal. However, you can redirect the output to a file by using the "-o" option followed by the filename. For example, to redirect the output of the "ls" command to a file called "output.txt", use the following command:
strace -o output.txt ls
Monitoring System Calls
Strace can also monitor all system calls made by the system. To do this, use the "-e" option followed by "all". For example, to monitor all system calls made by the system and output them to a file called "output.txt", use the following command:
strace -e all -o output.txt
Conclusion
In conclusion, Strace is a powerful tool for system analysis in Linux. By mastering the Strace command, you can gain better insights into the behavior of your system and optimize its performance. Whether you're a system administrator or a developer, Strace can help you identify issues and resolve them quickly. In this article, we have covered some of the basic usage and features of Strace, including filtering system calls, displaying signal information, displaying timestamps, and redirecting output.
However, Strace has many more options and features that can be used to gain deeper insights into the system's behavior. We recommend exploring the Strace man pages and documentation to learn more about its advanced usage.
Overall, mastering the Strace command is an essential skill for anyone working with Linux systems. With its ability to trace system calls, signals, and other related information, Strace is a powerful tool for debugging issues, investigating performance problems, and optimizing system behavior.