strace and ltrace — debugging

When logs don’t help, strace/ltrace are the safety net.

strace¶

strace ls /tmp
strace -p 1234
strace -e open,read,write ls /tmp
strace -c ls /tmp

Examples¶

strace -e openat ./app 2>&1 | grep error
strace -e write -p $(pgrep myapp)
strace -c -p $(pgrep myapp) # where it spends time

ltrace¶

ltrace ./my-program
ltrace -e malloc+free ./my-program

• -f = child processes
• -s 1000 = longer strings
• Use briefly in production

Ultimate debugging¶

strace will save hours of troubleshooting.