前言

• 如果需要在后台执行且关闭shell不退出，在程序启动命令中加入 &
• 如果开始没有加入 &，发现命令执行时间很长，可以参考本文

将进程切换到后台且不退出

1. 将进程切换到后台（Ctrl + Z）
2. 让进程在后台继续执行（bg x）
3. 使用exit命令退出当前shell，进程不退出

将进程暂停且切换到后台

使用Ctrl + Z将命令暂停切换到后台。Ctrl + Z 是将任务中止（暂停的意思）,但是此任务并没有结束,他仍然在进程中他只是维持挂起的状态

shell> wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
--2022-08-06 10:56:21--  https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
Resolving download.filezilla-project.org (download.filezilla-project.org)... 49.12.121.47, 2a01:4f8:242:52d0::2
Connecting to download.filezilla-project.org (download.filezilla-project.org)|49.12.121.47|:443... connected.
HTTP request sent, awaiting response... 200 OK
Length: 11854128 (11M) [application/x-msdos-program]
Saving to: ‘FileZilla_3.60.2_win64_sponsored-setup.exe.2’

 1% [>                                                                                   ] 122,880     30.2KB/s  eta 6m 19s 
^Z (输入Ctrl + Z)
[1]+  Stopped                 wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
1
2
3
4
5
6
7
8
9
10
11

查看后台的进程

shell> jobs -l
[1]+  Stopped                 wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
1
2

• 后台有1个已暂停的程序
• [1]表示进程在后台的编号为1

将进程切换到前台且继续执行

shell> fg 1
wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
 3% [====>                                                                                                                                                               ] 409,600      992B/s   in 6m 53s  

2022-08-06 11:03:16 (992 B/s) - Connection closed at byte 409600. Retrying.

--2022-08-06 11:03:17--  (try: 2)  https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe
Connecting to download.filezilla-project.org (download.filezilla-project.org)|49.12.121.47|:443... connected.
HTTP request sent, awaiting response... 206 Partial Content
Length: 11854128 (11M), 11444528 (11M) remaining [application/x-msdos-program]
Saving to: ‘FileZilla_3.60.2_win64_sponsored-setup.exe.2’

 7% [+++++=====>                                                                                                                                                         ] 860,160     28.1KB/s  eta 5m 16s
1
2
3
4
5
6
7
8
9
10
11
12
13

• fg 1中的1为进程在后台的编号

让进程在后台继续执行

shell> bg 1
[1]+ wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe &
 1% [>                                                                                                                                                                   ] 122,880      534B/s  eta 6h 5m   [ 
 5% [=======>                                                                                                                                                            ] 630,784     19.6KB/s  eta 73m 5s 
1
2
3
4

• bg 1中的1为进程在后台的编号

查看后台的进程:

[1]+  Running                 wget https://download.filezilla-project.org/client/FileZilla_3.60.2_win64_sponsored-setup.exe &
1

• 执行 bg 1后，系统在命令后面加入&符号
• 看到&符号后，此时可以通过exit命令退出当前shell。执行exit退出shell后，进程不退出。
• 另一shell，使用ps -ef|grep wget可查看到在后台运行的进程。