Linux Shell中判断进程是否存在的代码

1 利用pgrep 匹配名字复制代码

代码如下:

if test $( pgrep -f $1 | wc -l ) -eq 0

then

echo “进程不存在”

else

echo “存在进程”

fi

以下是补充内容：

当前系统中的进程：

apple@ubuntu:~$ ps -ef

UID PID PPID C STIME TTY TIME CMD

root 1 0 0 13:57 ? 00:00:02 /sbin/init

root 2 0 0 13:57 ? 00:00:00 [kthreadd]

root 3 2 0 13:57 ? 00:00:00 [migration/0]

root 4 2 0 13:57 ? 00:00:00 [ksoftirqd/0]

root 5 2 0 13:57 ? 00:00:00 [watchdog/0]

root 6 2 0 13:57 ? 00:00:00 [migration/1]

root 7 2 0 13:57 ? 00:00:00 [ksoftirqd/1]

root 8 2 0 13:57 ? 00:00:00 [watchdog/1]

root 9 2 0 13:57 ? 00:00:00 [events/0]

root 10 2 0 13:57 ? 00:00:00 [events/1]

root 11 2 0 13:57 ? 00:00:00 [khelper]

root 12 2 0 13:57 ? 00:00:00 [kstop/0]

root 13 2 0 13:57 ? 00:00:00 [kstop/1]

root 14 2 0 13:57 ? 00:00:00 [kintegrityd/0]

root 15 2 0 13:57 ? 00:00:00 [kintegrityd/1]

root 16 2 0 13:57 ? 00:00:00 [kblockd/0]

root 17 2 0 13:57 ? 00:00:00 [kblockd/1]

root 18 2 0 13:57 ? 00:00:00 [kacpid]

root 19 2 0 13:57 ? 00:00:00 [kacpi_notify]

root 20 2 0 13:57 ? 00:00:00 [cqueue]

root 21 2 0 13:57 ? 00:00:00 [ata/0]

root 22 2 0 13:57 ? 00:00:00 [ata/1]

root 23 2 0 13:57 ? 00:00:00 [ata_aux]

root 24 2 0 13:57 ? 00:00:00 [ksuspend_usbd]

root 25 2 0 13:57 ? 00:00:00 [khubd]

root 26 2 0 13:57 ? 00:00:00 [kseriod]

root 27 2 0 13:57 ? 00:00:00 [kmmcd]

root 28 2 0 13:57 ? 00:00:00 [btaddconn]

root 29 2 0 13:57 ? 00:00:00 [btdelconn]

root 30 2 0 13:57 ? 00:00:00 [pdflush]

root 31 2 0 13:57 ? 00:00:00 [pdflush]

root 32 2 0 13:57 ? 00:00:00 [kswapd0]

root 33 2 0 13:57 ? 00:00:00 [aio/0]

root 34 2 0 13:57 ? 00:00:00 [aio/1]

root 35 2 0 13:57 ? 00:00:00 [ecryptfs-kthrea]

root 38 2 0 13:57 ? 00:00:00 [pciehpd]

root 39 2 0 13:57 ? 00:00:00 [scsi_eh_0]

root 40 2 0 13:57 ? 00:00:00 [scsi_eh_1]

root 41 2 0 13:57 ? 00:00:00 [kstriped]

root 42 2 0 13:57 ? 00:00:00 [kmpathd/0]

root 43 2 0 13:57 ? 00:00:00 [kmpathd/1]

root 44 2 0 13:57 ? 00:00:00 [kmpath_handlerd]

root 45 2 0 13:57 ? 00:00:00 [ksnapd]

root 46 2 0 13:57 ? 00:00:00 [kondemand/0]

root 47 2 0 13:57 ? 00:00:00 [kondemand/1]

root 48 2 0 13:57 ? 00:00:00 [krfcommd]

root 256 2 0 13:57 ? 00:00:00 [mpt_poll_0]

root 717 2 0 13:57 ? 00:00:00 [scsi_eh_2]

root 753 2 0 13:57 ? 00:00:00 [kdmflush]

root 764 2 0 13:57 ? 00:00:00 [kdmflush]

root 795 2 0 13:57 ? 00:00:00 [kjournald]

root 915 1 0 13:57 ? 00:00:00 /sbin/udevd –daemon

root 1617 2 0 13:57 ? 00:00:00 [kpsmoused]

root 2166 1 0 13:57 tty4 00:00:00 /sbin/getty 38400 tty4

root 2167 1 0 13:57 tty5 00:00:00 /sbin/getty 38400 tty5

root 2172 1 0 13:57 tty2 00:00:00 /sbin/getty 38400 tty2

root 2173 1 0 13:57 tty3 00:00:00 /sbin/getty 38400 tty3

root 2174 1 0 13:57 tty6 00:00:00 /sbin/getty 38400 tty6

root 2244 1 0 13:57 ? 00:00:00 /usr/sbin/acpid -c /etc/acpi/eve

root 2259 1 0 13:57 ? 00:00:00 /usr/sbin/syslog-ng -p /var/run/

105 2279 1 0 13:57 ? 00:00:00 /bin/dbus-daemon –system

root 2311 1 0 13:58 ? 00:00:00 /usr/sbin/incrond -f /etc/incron

root 2381 1 0 13:58 ? 00:00:00 dhclient3 -e IF_METRIC=100 -pf /

root 2442 1 0 13:58 ? 00:00:00 /usr/sbin/sshd

root 2453 1 0 13:58 ? 00:00:00 /usr/lib/postfix/master

postfix 2465 2453 0 13:58 ? 00:00:00 pickup -l -t fifo -u -c

postfix 2468 2453 0 13:58 ? 00:00:00 qmgr -l -t fifo -u

108 2472 1 0 13:58 ? 00:00:00 /usr/sbin/hald

root 2475 1 0 13:58 ? 00:00:00 /usr/sbin/console-kit-daemon

root 2538 2472 0 13:58 ? 00:00:00 hald-runner

root 2567 2538 0 13:58 ? 00:00:00 hald-addon-input: Listening on /

root 2594 2538 0 13:58 ? 00:00:00 hald-addon-storage: polling /dev

root 2595 2538 0 13:58 ? 00:00:00 hald-addon-storage: no polling o

108 2600 2538 0 13:58 ? 00:00:00 hald-addon-acpi: listening on ac

daemon 2647 1 0 13:58 ? 00:00:00 /usr/sbin/atd

root 2672 1 0 13:58 ? 00:00:00 /usr/sbin/cron

root 2691 1 0 13:58 tty1 00:00:00 /sbin/getty 38400 tty1

root 2994 2442 0 14:11 ? 00:00:00 sshd: apple [priv]

apple 3003 2994 0 14:11 ? 00:00:00 sshd: apple@pts/0

apple 3004 3003 1 14:11 pts/0 00:00:00 -bash

apple 3024 3004 0 14:11 pts/0 00:00:00 ps -ef

apple@ubuntu:~$

1.ps -p

ps -p 根据给定的pid参数判断是否有这个进程，如果有这个进程正常退出，退出值0.如果没有这个进程异常退出，退出值1.

例如：

apple@ubuntu:~$ ps -p 2442

PID TTY TIME CMD

2442 ? 00:00:00 sshd

apple@ubuntu:~$ echo $?

0

apple@ubuntu:~$ ps -p 1234

PID TTY TIME CMD

apple@ubuntu:~$ echo $?

1

apple@ubuntu:~$

2.pgrep

pgrep根据给出的进程名判断是否有这个名字的进程。如果有这个名字的进程正常退出，退出值0.如果没有这个名字的进程异常退出，退出值1.

例如：

apple@ubuntu:~$ pgrep sshd

2442

2994

3003

apple@ubuntu:~$ echo $?

0

apple@ubuntu:~$ pgrep sshddd

apple@ubuntu:~$ echo $?

1

apple@ubuntu:~$

3./proc

每个进程都会在/proc下有一个以进程PID命名的目录。

例如：

apple@ubuntu:~$ ls /proc/2442

ls: cannot read symbolic link /proc/2442/cwd: Permission denied

ls: cannot read symbolic link /proc/2442/root: Permission denied

ls: cannot read symbolic link /proc/2442/exe: Permission denied

attr clear_refs cpuset exe io loginuid mountinfo net pagemap sched smaps status wchan

auxv cmdline cwd fd latency maps mounts oom_adj personality schedstat stat syscall

cgroup coredump_filter environ fdinfo limits mem mountstats oom_score root sessionid statm task

apple@ubuntu:~$

可以根据上面的事实，编写bash脚本判断一个进程是否存在。下面以第3个事实，编写脚本。其他的脚本类似。

复制代码

代码如下:

#!/bin/bash

if [ -z $1 ]

then

echo “Need a pid argument”

exit 1

fi

if [ -d /proc/$1 ];then

exit 0

else

exit 1

fi