Ten Linux commands you don't know (1)

The following may be the ten Linux commands you have never used. Very useful.

1) pgrep

There is a p in front of the pgrep name. We can guess that it is related to the process, and it is also a grep command related to the process. However, this command is mainly used to list process IDs. For example:

$ pgrep -u hchen2244122444

This command is equivalent:

1 ps -ef | egrep '^hchen' | awk '{print $2}'

2) pstree

This command can list processes in a tree. As follows:

[hchen@RHELSVR5 ~]$ pstreeinit-+-acpid|-auditd-+-python| `-{auditd}|-automount---4*[{automount}]|-backup.sh---sleep|-dbus-daemon|-events/0|-events/1|-hald---hald-runner---hald-addon-acpi|-httpd---10*[httpd]|-irqbalance|-khelper|-klogd|-ksoftirqd/0|-ksoftirqd/1|-kthread-+-aio/0|-aio/1|-ata/0|-ata/1|-ata_aux|-cqueue/0|-cqueue/1|-kacpid|-kauditd|-kblockd/0|-kblockd/1|-kedac|-khubd|-6*[kjournald]|-kmirrord|-kpsmoused|-kseriod|-kswapd0|-2*[pdflush]|-scsi_eh_0|-scsi_eh_1|-xenbus| `-xenwatch|-migration/0|-migration/1|-6*[mingetty]|-3*[multilog]|-mysqld_safe---mysqld---9*[{mysqld}]|-smartd|-sshd---sshd---sshd---bash---pstree|-svscanboot---svscan-+-3*[supervise---run]|-supervise---qmail-send-+-qmail-clean|-qmail-lspawn| `-qmail-rspawn| `-2*[supervise---tcpserver]|-syslogd|-udevd|-watchdog/0|-watchdog/1-xinetd