下面由linux系統教程欄目給大家介紹linux tty/pts及其作用區別，希望對需要的朋友有所幫助！
Linux TTY/PTS概述
+----------+ Physical Line +----------+ | teletype |<--------------------->| teletype | +----------+ +----------+
+----------+ +----------+ +-------+ Physical Line +-------+ +------+ | | | Terminal |<->| Modem |<--------------------->| Modem |<->| UART |<->| Computer | +----------+ +-------+ +-------+ +------+ | | +----------+
+-----------------------------------------------+ | Kernel | | +--------+ | | +--------+ +------------+ | | | +----------------+ | | UART | | Line | | TTY |<---------->| User process A | <------>| |<->| |<->| | | +----------------+ | | driver | | discipline | | driver |<---------->| User process B | | +--------+ +------------+ | | | +----------------+ | +--------+ | | | +-----------------------------------------------+
+----------------+ | TTY Driver | | | | +-------+ | +----------------+ +------------+ | | |<---------->| User process A | | Terminal A |<--------->| ttyS0 | | +----------------+ +------------+ | | |<---------->| User process B | | +-------+ | +----------------+ | | | +-------+ | +----------------+ +------------+ | | |<---------->| User process C | | Terminal B |<--------->| ttyS1 | | +----------------+ +------------+ | | |<---------->| User process D | | +-------+ | +----------------+ | | +----------------+
#先用tty命令看看當前bash關聯到了哪個tty dev@debian:~$ tty /dev/pts/1 #看tty都被哪些進程打開了 dev@debian:~$ lsof /dev/pts/1 COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME bash 907 dev 0u CHR 136,1 0t0 4 /dev/pts/1 bash 907 dev 1u CHR 136,1 0t0 4 /dev/pts/1 bash 907 dev 2u CHR 136,1 0t0 4 /dev/pts/1 bash 907 dev 255u CHR 136,1 0t0 4 /dev/pts/1 lsof 1118 dev 0u CHR 136,1 0t0 4 /dev/pts/1 lsof 1118 dev 1u CHR 136,1 0t0 4 /dev/pts/1 lsof 1118 dev 2u CHR 136,1 0t0 4 /dev/pts/1 #往tty里面直接寫數據跟寫標準輸出是一樣的效果 dev@dev:~$ echo aaa > /dev/pts/2 aaa
Input +--------------------------+ R/W +------+ ----------->| |<---------->| bash | | pts/1 | +------+ <-----------| |<---------->| lsof | Output | Foreground process group | R/W +------+ +--------------------------+
+-----------------------------------------+ | Kernel | | +--------+ | +----------------+ +----------+ | +-------------------+ | tty1 |<---------->| User processes | | Keyboard |--------->| | +--------+ | +----------------+ +----------+ | | Terminal Emulator |<->| tty2 |<---------->| User processes | | Monitor |<---------| | +--------+ | +----------------+ +----------+ | +-------------------+ | tty3 |<---------->| User processes | | +--------+ | +----------------+ | | +-----------------------------------------+
+----------+ +------------+ | Keyboard |------>| | +----------+ | Terminal | | Monitor |<------| | +----------+ +------------+ | | ssh protocol | ↓ +------------+ | | | ssh server |--------------------------+ | | fork | +------------+ | | ↑ | | | | write | | read | | | | +-----|---|-------------------+ | | | | | ↓ | ↓ | +-------+ | +-------+ | +--------+ | pts/0 |<---------->| shell | | | | +-------+ | +-------+ | | ptmx |<->| pts/1 |<---------->| shell | | | | +-------+ | +-------+ | +--------+ | pts/2 |<---------->| shell | | +-------+ | +-------+ | Kernel | +-----------------------------+
#pty（pseudo terminal device）由兩部分構成，ptmx是master端，pts是slave端， #進程可以通過調用API請求ptmx創建一個pts，然后將會得到連接到ptmx的讀寫fd和一個新創建的pts， #ptmx在內部會維護該fd和pts的對應關系，隨后往這個fd的讀寫會被ptmx轉發到對應的pts。 #這里可以看到sshd已經打開了/dev/ptmx dev@debian:~$ sudo lsof /dev/ptmx COMMAND PID USER FD TYPE DEVICE SIZE/OFF NODE NAME sshd 1191 dev 8u CHR 5,2 0t0 6531 /dev/ptmx sshd 1191 dev 10u CHR 5,2 0t0 6531 /dev/ptmx sshd 1191 dev 11u CHR 5,2 0t0 6531 /dev/ptmx
+----------+ +------------+ | Keyboard |------>| | +----------+ | Terminal |--------------------------+ | Monitor |<------| | fork | +----------+ +------------+ | | ↑ | | | | write | | read | | | | +-----|---|-------------------+ | | | | | ↓ | ↓ | +-------+ | +-------+ | +--------+ | pts/0 |<---------->| shell | | | | +-------+ | +-------+ | | ptmx |<->| pts/1 |<---------->| shell | | | | +-------+ | +-------+ | +--------+ | pts/2 |<---------->| shell | | +-------+ | +-------+ | Kernel | +-----------------------------+
+----------+ +------------+ | Keyboard |------>| | +----------+ | Terminal | | Monitor |<------| | +----------+ +------------+ | | ssh protocol | ↓ +------------+ | | | ssh server |--------------------------+ | | fork | +------------+ | | ↑ | | | | write | | read | | | | +-----|---|-------------------+ | | ↓ | | ↓ | +--------+ +-------+ | +-------+ fork +-------------+ | | ptmx |<->| pts/0 |<---------->| shell |-------->| tmux client | | +--------+ +-------+ | +-------+ +-------------+ | | | | ↑ | +--------+ +-------+ | +-------+ | | | ptmx |<->| pts/2 |<---------->| shell | | | +--------+ +-------+ | +-------+ | | ↑ | Kernel | ↑ | +-----|---|-------------------+ | | | | | | |w/r| +---------------------------+ | | | | fork | | ↓ | | +-------------+ | | | | | tmux server |<--------------------------------------------+ | | +-------------+
dev@dev:~$ stty -a speed 38400 baud; rows 51; columns 204; line = 0; intr = ^C; quit = ^; erase = ^?; kill = ^U; eof = ^D; eol = M-^?; eol2 = M-^?; swtch = <undef>; start = ^Q; stop = ^S; susp = ^Z; rprnt = ^R; werase = ^W; lnext = ^V; discard = ^O; min = 1; time = 0; -parenb -parodd -cmspar cs8 -hupcl -cstopb cread -clocal -crtscts -ignbrk -brkint -ignpar -parmrk -inpck -istrip -inlcr -igncr icrnl ixon -ixoff -iuclc ixany imaxbel -iutf8 opost -olcuc -ocrnl onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0 isig icanon iexten echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl echoke -flusho -extproc
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