To show the process ID of a process by the string name

pgrep <processName>

To kill a process by the name of the process

pkill <processName>

To listen to see which process ID / name is listening on a port

netstat -tulpn | grep :25

25 denotes the port number

strace /usr/bin/ld -lsasl2

ln -s /usr/local/lib/libsasl2.so /usr/lib/libsasl2.so

/usr/bin/ld -lsasl2

To trace system calls from commands, ie,

strace df -h

To trace Linux Process PID

strace -p 42

To get a summary of a Linux process

strace -c -p 42

To print instruction pointer during system call

strace -i df -h

To show time of day for each output line

strace -t df -h

• some commands working with strace
• some useful commands when working with strace, see 🙈
• StackExchange QnA - recovering from a grub rescue crash
• Ubuntu.com - Grub2 Troubleshooting