The Linux system is slow because of high CPU utilization and memory is running low? Now, how to use the ps command to find out what are the running processes with top CPU and memory usage?
Well, there are no short of command line tools and GUI programs to find these out. But I think the ps command is one of the top 10 Linux commands and thus believe that most of UNIX/Linux users have came across ps command in the first day of UNIX/Linux introduction class.
But, how many users bother to type man ps and vet through the lengthy manual page for the available option switches?
Customize the ps command output for the subject
I have tested this in RHEL5 Linux command prompt:
where the SFS (short for Standard Format Specifiers) can be one or more of the following keywords. Take note that not all of these SFS are available for sorting, e.g. time.
The ps command example
To find out top processes in term of physical memory usage in Linux system, type this:
As the standard format specifiers
Other than the 7 standard format specifiers mentioned above for used with -o option switch of ps command, there are many more (e.g. cputime, bsdtime, etc) covered in
Well, there are no short of command line tools and GUI programs to find these out. But I think the ps command is one of the top 10 Linux commands and thus believe that most of UNIX/Linux users have came across ps command in the first day of UNIX/Linux introduction class.
But, how many users bother to type man ps and vet through the lengthy manual page for the available option switches?
Customize the ps command output for the subject
I have tested this in RHEL5 Linux command prompt:
ps -eo SFS --sort SFS
where the SFS (short for Standard Format Specifiers) can be one or more of the following keywords. Take note that not all of these SFS are available for sorting, e.g. time.
pidto display the process ID of the process.
startto display the time of command was started.
timeis an alias of cputime and is better alternative to bsdtime; to display the cumulative CPU time (user and system) in [dd-]hh:mm:ss format.
rssto display the process’s Resident Set Size (RSS) in KB. RSS is regarded as non-swapped physical memory taken by a process.
vszto display virtual memory size of the process in KB, excluding the device mappings.
cmdto display the running command or process and its specified arguments.
commto display the running command or process but exclude its specified arguments.
The ps command example
To find out top processes in term of physical memory usage in Linux system, type this:
ps -eo pid,rss,comm --sort rss
As the standard format specifiers
time is not available for sorting, it is a bit troublesome if uses ps command to find top CPU usage of processes. E.g. to find Linux processes that use more than 5 minutes of CPU time: ps -eo pid,time,comm | grep -v 00:0[0-5]
Other than the 7 standard format specifiers mentioned above for used with -o option switch of ps command, there are many more (e.g. cputime, bsdtime, etc) covered in
man ps that might be interesting and useful to you.
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2013 •
this is really not the tool for this job. ‘top’ is your friend.