The perfect strace command
Posted on Fri 17 October 2025 in Operating Systems, Debugging • Tagged with Operating Systems, Debugging
The Linux utility strace is essential for diagnosing process–kernel interactions, but its default output is often unusable. The key to effective debugging is using a specific set of flags that transform raw system call data into a structured, time‑stamped, and annotated log.
According to Avikam Rozenfeld in this presentation, here is the essential command template, followed by a breakdown of why each flag is critical:
strace -f -s 256 -o trace.log -tt -T -y <your_command_here>
Flags and why they matter:
- 
-f — Follow children
Purpose: Trace child processes spawned byfork/clone.
Key benefit: Ensures you trace the entire application flow (e.g., piped commands). - 
-s 256 — Increase string size
Purpose: Increase the string output limit (default 32 bytes) to 256 bytes.
Key benefit: Prevents truncation of file paths and data being read or written. - 
-o
— Output to file 
Purpose: Redirect allstraceoutput to a specified log file (e.g.,trace.log).
Key benefit: Separates trace output from the program's standard output for easier analysis. - 
-tt — Precise timestamp
Purpose: Prefix every line … 
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