strace command in Linux
The strace command in Linux is a powerful utility used to trace system calls and signals made by a program. By monitoring interactions between processes and the kernel, strace helps diagnose and troubleshoot issues efficiently. This tool can be invaluable for understanding the behavior of programs, identifying performance bottlenecks, and debugging complex problems. By providing detailed insight into how programs interact with the operating system, strace is a key asset for system administrators and developers alike.
strace Syntax:
Section titled “strace Syntax:”strace [options] command [args]Linux strace Options:
Section titled “Linux strace Options:”| Option | Description |
|---|---|
| -c | Print a summary of the counts of each system call and exit |
| -f | Trace child processes as they are created by currently traced processes |
| -o filename | Write the trace output to the specified filename |
| -p pid | Attach to the process with the specified process ID and begin tracing |
| -s size | Specify the maximum string size to print (default is 32) |
| -t | Prefix each line of the trace with the time of day |
| -T | Prefix each line with the time spent in each system call |
| -e trace=set | Perform a filtered trace based on the specified set of system calls |
| -y | Print paths associated with file descriptor arguments |
| -E var=value | Set the value of an environment variable for the traced process |
| -h | Display help message and exit |
strace Parameters:
Section titled “strace Parameters:”| Parameter | Description |
|---|---|
| command | The command to be traced |
| args | Optional arguments to be passed to the command |
How to use strace command:
Section titled “How to use strace command:”Trace a Process by PID
Section titled “Trace a Process by PID”strace -p <PID>This command traces the system calls made by the process with the specified PID.
Trace a Command
Section titled “Trace a Command”strace lsExecutes the “ls” command while tracing the system calls it makes.
Trace a Process and Its Children
Section titled “Trace a Process and Its Children”strace -f commandTraces the specified command and any child processes it spawns.
Save strace Output to a File
Section titled “Save strace Output to a File”strace -o output.txt commandRedirects the strace output of the command to the specified file.
Display Time Taken by Each System Call
Section titled “Display Time Taken by Each System Call”strace -T commandShows the time taken by each system call made by the specified command.
Trace System Calls related to File I/O
Section titled “Trace System Calls related to File I/O”strace -e trace=file commandTraces only the system calls related to file operations made by the specified command.
Trace Only Specific System Calls
Section titled “Trace Only Specific System Calls”strace -e trace=open,read commandTraces only the “open” and “read” system calls made by the specified command.
Filter Output for a Specific System Call
Section titled “Filter Output for a Specific System Call”strace -e open commandFilters the strace output to display only the system call “open” made by the specified command.
How do I use strace in Linux?
Section titled “How do I use strace in Linux?”To use the strace command in Linux, execute the following command:
strace lsWhat is the purpose of the strace command in Linux?
Section titled “What is the purpose of the strace command in Linux?”The strace command in Linux is used to trace and display the system calls and signals made by a process. It is helpful for troubleshooting and understanding the behavior of programs.
How can I trace a specific process with strace in bash?
Section titled “How can I trace a specific process with strace in bash?”To trace a specific process with strace in bash, use the following command:
strace -p <PID>How do I save the strace output to a file in Linux?
Section titled “How do I save the strace output to a file in Linux?”To save the strace output to a file in Linux, run the command with output redirection, like this:
strace ls > output.txtCan strace be used to trace multiple processes simultaneously in Linux?
Section titled “Can strace be used to trace multiple processes simultaneously in Linux?”Yes, strace can be used to trace multiple processes simultaneously in Linux by specifying multiple process IDs (PIDs) separated by commas.
strace -p <PID1>,<PID2>How can I show timestamps with strace output in Linux?
Section titled “How can I show timestamps with strace output in Linux?”To show timestamps with strace output in Linux, use the -t option in the command:
strace -t lsIs it possible to follow forks with strace in bash?
Section titled “Is it possible to follow forks with strace in bash?”Yes, it is possible to follow forks with strace in bash using the -f option in the command. This option traces child processes as they are created.
strace -f lsHow can I display both system calls and signals with strace in Linux?
Section titled “How can I display both system calls and signals with strace in Linux?”To display both system calls and signals with strace in Linux, use the -v option in the command:
strace -v lsApplications of the strace command
Section titled “Applications of the strace command”- Debugging system calls and signals
- Tracing and analyzing the behavior of programs
- Troubleshooting and identifying issues with applications
- Monitoring system calls and function calls
- Analyzing the performance of programs
- Studying the interactions between processes and the kernel
- Understanding the flow of data between processes and the system