HPUX - Shell Basic

$ ps

   PID TTY       TIME COMMAND

 12608 pts/tg    0:00 telnetd

 13471 pts/tg    0:00 ps

 12609 pts/tg    0:00 sh      <--- shell

Alias : command line interpretor [ alias dir=ls, alias rm="rm -i", alias cp="cp -i", unalias dir ]

{

$ dir

README.exrc     color3          funfile         mod5.dir        peach

abcdefXlmnop    color4          funfile.123     myfile          prog1

$ alias rm='rm -i'

$ rm b*

backup: ? (y/n)

}

File Name Completion : fra "ESC" "ESC" -> frankenstein

command history : command "history"

recalling commands : Press "ESC", k scrolls backward through the command history, scrolls forward through the command history [then, work as command mode]

env : environment describes your session to the programs you run

set : describes your local variables and environment variables

setting Shell variables

syntax : name=value

{ 

$ color=red

$ set

....

color=red

....

$ color=blue

$ set

....

color=blue

....

}

TERM variable : Describes your terminal type and screen size to the programs you run

{

$ env

...

TERM=vt100    [terminal model, virtual terminal 100]

...

$ TERM=yohan

....

TERM=yohan

....

command clear, vi won't work [screen oriented file won't work]

}

PATH variable : A list of directories where the shell will search for the commands you type

{

$ env

...

PATH=/usr/bin/:/usr/bin/X11:/usr/contrib/bin:.

...

$ ping 59.29.225.254

sh: ping:  not found.

$ whereis ping

ping: /usr/sbin/ping /usr/share/man/man1m.Z/ping.1m

$ /usr/sbin/ping 59.29.225.254

PING 59.29.225.254: 64 byte packets

64 bytes from 59.29.225.254: icmp_seq=0. time=12. ms

64 bytes from 59.29.225.254: icmp_seq=1. time=0. ms

64 bytes from 59.29.225.254: icmp_seq=2. time=0. ms

64 bytes from 59.29.225.254: icmp_seq=3. time=0. ms

....

}

Common Variable Assignments

OLDPWD=/tmp

PWD=/home/user11

PS1=

HISTFILE=$HOME/.sh_history

...

What Happens at Login?

$ PS1='$PWD $ '

/home/user11 $ 

/home/user11 $ 

/home/user11 $ exit

write at process on memory

during login process shell(= /usr/bin/sh) reads .profile configuration 

$ vi .profile

add PS1='$PWD $ '

1 getty 1) display /etc/issue  2) login prompt "login :"

2 login 1) id / password check 

{

$ more /etc/passwd 

....

user10:It3J7kO99AKcc:310:301:student:/home/user10:/usr/bin/sh

user11:JHzzLKLoXDPUs:311:301:student:/home/user11:/usr/bin/sh

....

username:passwd:UID:GID:comment    :HOME directory :shell

}

       2) 홈디렉토리 위치

       3) 쉘프로그램 실행

3 /usr/bin/sh 1)read /etc/profile  (managed by root)

       2) $HOME/.profile (managed by owner, $home/.bash_prfile in Linux)  // export 사용시 자식쉘 생성시 참조

       3) $HOME/.shrc or /.kshrc , /.bashrc (managed by owner) // 자식쉘 생성 시 참조

[ 1) -> 2) -> 3) 순서로 참조, 겹친 변수 설정들은 가장 최신으로 참조한 선언에 따른다.]

{

.shrc를 읽는 조건

$ vi .profile

add export ENV=$HOME/.shrc

}

where date : searches a list of directories for a command

which date : 어디에 있는 파일(명령어)을 사용하는지 보여줌