ps command usage examples in Linux
The ps command is for the process status. ps gives the status of currently executing processes on a Linux or Unix system. There are multiple options for the ps command that help in getting the process information of interest.
top Command in Linux
The top command is useful for monitoring a Linux or Unix system continuously for processes that take more system resources like the CPU time and the memory. top periodically updates the display showing the high resource consuming processes at the top.
Alarm, sleep and High Resolution Timers
Software systems often need to act based on time. The accuracy and precision of time maintained by a system is important. Alarms, sleep and high resolution timers provide a framework for application programs to carry out time-critical tasks.
Synchronizing Files Between Multiple Computers Using Unison
As we work on multiple computers, we need to transfer the work done from one computer to another. Doing this manually is prone to error. This synchronization can be automated using Unison. Unison provides bidirectional synchronization between two computers.
Linux process execution time
As a process executes, it takes up the CPU time which is also called the execution time or the processor time. The
times system call and the clock library function
can be used by the process to find its execution time.
sar in Linux
The sar command under Linux and Unix systems gives the system activity reports. The sar command gives statistics regarding the CPU, I/O, paging, devices, memory, swap space, network, run queue length and load average, interrupts and power management.
Load average, reported by commands like top, uptime and w, is explained. Load average is an indication of whether the system resources (mainly the CPU) are adequately available for the processes (system load) that are running, runnable or in uninterruptible sleep states during the previous n minutes.
rsync is used for synchronizing the source files with the corresponding files at the destination. The source and destination may be on the same host, in which case rsync becomes an advanced copy command. Or, the destination may be a networked remote host. rsync uses the delta encoding technique for copying files; for files existing at the destination, only the differences from the source are transferred.