I can't understand what these two lines are doing?
When I execute the first line nothing is output. I get that the command is being directed somewhere that is not shown. And when I execute the echo $? line I get a number. Not sure what this number means though? Is this command checking if I can successfully login to this server or not?
Also, is there a way to concatenate the two lines into one command line instruction to return the value?
Thank you.
Last edited by jim mcnamara; 10-09-2019 at 07:37 PM..
We use a UNIX-based system (Lawson) at work and I was given this command to request a data extract from the db admin. The only thing I really understand is the last line as it appears to be joining the files created from the first three lines into one. Is there anyone who can help me breakdown the... (4 Replies)
Guys,
I am trying to understand the sed command here.
adx001 $ a=/clocal/dctrdata/user/dctrdat1/trdroot/recouncil
adx001 $ b=`echo $a | sed 's/\//\\\\\//g'`
adx001 $ echo $b
\/clocal\/dctrdata\/user\/dctrdat1\/trdroot\/recouncil
The sed command i took it from the script.
Please... (3 Replies)
Hi Guys,
I like to know if i have a process which triggers 10 different child processes.
How to identify out of the 11 processes running which is the parent process and what are the child process?
And if i kill the parent process will the child process be killed.. if not is there a way to... (2 Replies)
hi
i was moving a file from one directory to another with the following cmmand
mv /home/hsghh/dfd/parent/file.txt .
while doing so i i accidently
mv /home/hsghh/dfd/dfd .
although i gave ctrl c and terminate the move command some of the file are missing in the parent directory and... (1 Reply)
Hi
I have a questions related 2 commands : 'du' and 'ls'.
Why is the difference between output of 'du' and 'ls' cmd's ?
Command 'du' :
------------------
jakubn@server1 /home/jakubn $ du -s *
4 engine.ksh
1331 scripts
'du -s *' ---> shows block count size on disk (512 Bytes... (5 Replies)
I want to understand what does this command do:confused::confused: find . \( -type f -o -type 1 \) Plz someone explain me ! Thanks much in advance!! (2 Replies)
Hi Friends,
I need a small help in understanding the below sed command.
$ cat t4.txt
1 root 1 58 0 888K 368K sleep 4:06 0.00% init
1 root 1 58 0 888K 368K sleep 4:06 0.00% init last
$ sed 's/*$//' t4.txt
1 root 1 58 0 888K ... (3 Replies)
Dear All members,
i have some trouble here, i want to ask your help. The case is:
I have some data, it's like:
-ABCD1234
-ABCD1235
-ABCD1237
-BCDE1111
-BCDE1112
-BCDE1114
there is some missing data's sequence (the format is: ABCD = name 1234 = sequence).
I want to print the... (2 Replies)
Hello
I am working on a Change request and Stuck at a point. The below awk command is used in the function.
float_test ( ) {
echo | awk 'END { exit ( !( '"$1"')); }'
}
I understand that awk 'END' is used to add one line at the end and exit is used to end the script with an error... (4 Replies)
Hello,
I have a directory where sometimes appear a certain file name - and I'd like to be notified by email when that happens... so what command or script I may use?
e.g. if there's a file named "adam" in the directory named "dir1" then send a mail to "abc@abc.com".. it needs to permanently... (5 Replies)
Discussion started by: netrom
5 Replies
LEARN ABOUT MINIX
init
INIT(8) System Manager's Manual INIT(8)NAME
init - grandparent of all processes
DESCRIPTION
The first program started by Minix is init. The actions performed by init can be summarized by this pseudo shell program:
# Open 0, 1, 2.
exec </dev/null >/dev/log 2>&1
# Run the system initialization script.
sh /etc/rc $bootopts
>/etc/utmp
echo reboot >>/usr/adm/wtmp
while :; do
# Wait for a process to exit, but don't always block.
wait
# Record logout. (Not in this dumb way, of course.)
if "pid is in my tables" $pid
then
echo "logout $pid" >/etc/utmp
echo "logout $pid" >>/usr/adm/wtmp
fi
# Start a new session.
while read line type getty init
do
if idle $line
then
$init ... <$tty >$tty
$getty <$tty >$tty 2>&1 &
pid=$!
"add pid to tables" $pid
echo "login $line $pid" >/etc/utmp
echo "login $line $pid" >>/usr/adm/wtmp
fi
done < /dev/ttytab
done
The first action of init is to run /etc/rc to initialize the system as described in boot(8). Init then enters its main loop where it waits
for processes to exit, and starts processes on each enabled terminal line. The file /etc/ttytab contains a list of terminal devices, their
terminal types, the program to execute on them to allow one to login (usually getty(8)), and the program to execute first to initialize the
line (usually stty(1)). These fields may be left out to indicate that a line is disabled or that initialization is not necessary. The
commands are searched using the path /sbin:/bin:/usr/sbin:/usr/bin.
Init accepts several signals that must be sent to process id 1. (It is the first process, so natually its process id is 1.) The signals
are:
SIGHUP When receiving a hangup signal, init will forget about errors and rescan ttytab for processes to execute. Init normally rescans
ttytab each time it feels the need to respawn a process, so the hangup signal is only needed if a line has been shut down, or after
a terminate signal. Note that after turning a line off you will have to kill the process running on that line manually, init
doesn't do that for you.
SIGTERM
Normally sent by programs that halt or reboot Minix. Causes init to stop spawning new processes.
SIGABRT
Sent by the keyboard driver when the CTRL-ALT-DEL key combination is typed. Causes init to run the shutdown command. A second
abort signal makes init halt the system directly with a system call. The keyboard driver halts the system, without a sync, after
the third CTRL-ALT-DEL.
Minix vs. Minix-vmd
There are a few differences between standard Minix and Minix-vmd on how init is run. The /etc/rc file is executed under standard Minix
with input connected to /dev/console, but under Minix-vmd this is still /dev/null. This means that under Minix-vmd processes must be
reconnected to /dev/console with the intr program if they need user interaction. Minix-vmd passes the value of the bootopts boot variable
to /etc/rc. Standard Minix does not.
FILES
/etc/ttytab List of terminals devices.
/etc/utmp List of currently logged in users.
/usr/adm/wtmp Login/logout history.
SEE ALSO ttytab(5), utmp(5), getty(8), stty(1), boot(8).
AUTHOR
Kees J. Bot (kjb@cs.vu.nl)
INIT(8)