skill, snice – send a signal or report process status

A UNIX Command
$skill
Usage:   skill [signal to send] [options] process selection criteria
Example: skill -KILL -v pts/*

The default signal is TERM. Use -l or -L to list available signals.
Particularly useful signals include HUP, INT, KILL, STOP, CONT, and 0.
Alternate signals may be specified in three ways: -SIGKILL -KILL -9

General options:
-f  fast mode            This is not currently useful.
-i  interactive use      You will be asked to approve each action.
-v  verbose output       Display information about selected processes.
-w  warnings enabled     This is not currently useful.
-n  no action            This only displays the process ID.

Selection criteria can be: terminal, user, pid, command.
The options below may be used to ensure correct interpretation.
-t  The next argument is a terminal (tty or pty).
-u  The next argument is a username.
-p  The next argument is a process ID number.
-c  The next argument is a command name.
$skill -l
HUP INT QUIT ILL TRAP ABRT BUS FPE KILL USR1 SEGV USR2 PIPE ALRM TERM STKFLT
CHLD CONT STOP TSTP TTIN TTOU URG XCPU XFSZ VTALRM PROF WINCH POLL PWR SYS
$ps aux | grep xine
jeffrin   2844  2.9  1.4 661236 29460 pts/3    Sl   20:44   0:00 xine
jeffrin   2866  0.0  0.0 112944   816 pts/1    S+   20:44   0:00 grep xine
$skill 2844
$ps aux | grep xine
jeffrin   2869  0.0  0.0 112944   820 pts/1    S+   20:44   0:00 grep xine
$

UNIX Explanation
The default  signal for  skill is TERM.  Use -l or  -L to
list  available  signals.   Particularly  useful  signals
include  HUP, INT,  KILL, STOP,  CONT, and  0.  Alternate
signals  may  be specified  in  three  ways: -9  -SIGKILL
-KILL.

parameter tcp_retries1

A UNIX Parameter
$cat /proc/sys/net/ipv4/tcp_retries1
3
$echo 4 > /proc/sys/net/ipv4/tcp_r

Parameter Definition
This value influences the  time, after which TCP decides,
that  something  is   wrong  due  to  unacknowledged  RTO
retransmissions,  and  reports   this  suspicion  to  the
network   layer.   RFC   1122  recommends   at   least  3
retransmissions, which is the default.

Parameter Code Internals


snippet 1
{
.procname = "tcp_retries1",
.data = &sysctl_tcp_retries1,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec_minmax,
.extra2 = &tcp_retr1_max
},

snippet 2
if (retransmits_timed_out(sk, sysctl_tcp_retries1, 0, 0)) {
/* Black hole detection */
tcp_mtu_probing(icsk, sk);

dst_negative_advice(sk);
}


Related From Research Paper
In this paper we have investigated TCP behavior in a 802.11b wireless Infrastructure network by means of experiments in a wireless network testbed. We have compared results obtained with similar experiments done in NS2 simulator. We conclude that TCP ACK skipping indeed improves TCP performance in real-life wireless LANs. Although the original goal was to explore the simultaneous-send problem reported in [1], several other insights were also obtained. The NS2 simulations showed the simultaneous-send problem manifest when MAC retries were disabled. However we were unable to reproduce the NO MAC retries case. Unlike in the NS2 simulator, various status indicators cannot be tracked in real experimentation. Instead the simultaneous-send phenomenon was observed using standalone network sniffers.
source: Experimental Evaluation of the TCP Simultaneous-Send Problem in 802.11 Wireless Local Area Networks Sumathi Gopal WINLAB, Rutgers University 73, Brett Road Piscataway, NJ 08854-8048 001 609 720 1202 sumathi@winlab.rutgers.edu Dipankar Raychaudhuri WINLAB, Rutgers University 73, Brett Road Piscataway, NJ 08854-8048 001 732 445 0877 ray@winlab.rutgers.edu

hcitool – configure Bluetooth connections

A UNIX Command
$hcitool
hcitool - HCI Tool ver 4.89
Usage:
	hcitool [options]  [command parameters]
Options:
	--help	Display help
	-i dev	HCI device
Commands:
	dev 	Display local devices
	inq 	Inquire remote devices
	scan	Scan for remote devices
	name	Get name from remote device
	info	Get information from remote device
	spinq	Start periodic inquiry
	epinq	Exit periodic inquiry
	cmd 	Submit arbitrary HCI commands
	con 	Display active connections
	cc  	Create connection to remote device
	dc  	Disconnect from remote device
	sr  	Switch master/slave role
	cpt 	Change connection packet type
	rssi	Display connection RSSI
	lq  	Display link quality
	tpl 	Display transmit power level
	afh 	Display AFH channel map
	lp  	Set/display link policy settings
	lst 	Set/display link supervision timeout
	auth	Request authentication
	enc 	Set connection encryption
	key 	Change connection link key
	clkoff	Read clock offset
	clock	Read local or remote clock
	lescan	Start LE scan
	lecc	Create a LE Connection
	ledc	Disconnect a LE Connection

For more information on the usage of each command use:
	hcitool  --help

UNIX Explanation
hcitool  is used to  configure Bluetooth  connections and
send  some special  command to  Bluetooth devices.  If no
command is  given, or if  the option -h is  used, hcitool
prints some usage information and exits.

basename – strip directory and suffix from filenames

A UNIX Command
$basename
basename: missing operand
Try `basename --help' for more information.
$basename /usr/bin/
bin
$basename /usr/
usr
$
$basename /usr/bin/less
less
$basename /usr/include/ma
malloc.h  math.h
$basename /usr/include/math.h
math.h
$basename /usr/include/math.h .
math.h
$basename /usr/include/math.h .h
math
$basename /usr/lib/libgccpp.so.1
libgccpp.so.1
$basename /usr/lib/libgccpp.so.1 .1
libgccpp.so
$

UNIX Explanation
`basename' removes any leading directory components from NAME.
Synopsis:

     basename NAME [SUFFIX]

If SUFFIX  is specified  and is identical  to the  end of
NAME, it is  removed from NAME as well.   Note that since
trailing  slashes are removed  prior to  suffix matching,
SUFFIX   will  do   nothing  if   it   contains  slashes.
`basename' prints the result on standard output.

Together, `basename' and `dirname' are designed such that
if `ls  "$name"' succeeds, then the  command sequence `cd
"$(dirname  "$name")";  ls  "$(basename "$name")"'  will,
too.   This  works   for  everything  except  file  names
containing a trailing newline.

POSIX allows the implementation  to define the results if
NAME  is  empty  or   `//'.   In  the  former  case,  GNU
`basename' returns the empty string.  In the latter case,
the result is `//' on platforms where // is distinct from
/, and `/' on platforms where there is no difference.


grog – guess options for groff command

A UNIX Command
$groff /usr/share/man/man7/pipe.7 | more
%!PS-Adobe-3.0
%%Creator: groff version 1.21
%%CreationDate: Fri Jul 15 18:18:46 2011
%%DocumentNeededResources: font Times-Roman
%%+ font Times-Bold
%%+ font Times-Italic
%%DocumentSuppliedResources: procset grops 1.21 0
%%Pages: 1
%%PageOrder: Ascend
%%DocumentMedia: Default 595 842 0 () ()
%%Orientation: Portrait
%%EndComments
%%BeginDefaults
%%PageMedia: Default
%%EndDefaults
%%BeginProlog
%%BeginResource: procset grops 1.21 0
%!PS-Adobe-3.0 Resource-ProcSet
/setpacking where{

$grog /usr/share/man/man7/pipe.7 | more
groff -man /usr/share/man/man7/pipe.7 
$groff -man /usr/share/man/man7/pipe.7 | more
%!PS-Adobe-3.0
%%Creator: groff version 1.21
%%CreationDate: Fri Jul 15 18:22:07 2011
%%DocumentNeededResources: font Times-Roman
%%+ font Times-Bold
%%+ font Times-Italic
%%DocumentSuppliedResources: procset grops 1.21 0
%%Pages: 2
%%PageOrder: Ascend
%%DocumentMedia: Default 595 842 0 () ()
%%Orientation: Portrait
%%EndComments
%%BeginDefaults
%%PageMedia: Default
%%EndDefaults
%%BeginProlog
%%BeginResource: procset grops 1.21 0
%!PS-Adobe-3.0 Resource-ProcSet

UNIX Explanation
grog reads  the input (file names or  standard input) and
guesses  which  of the  groff(1)  options  are needed  to
perform   the  input   with  the   groff   program.   The
corresponding groff command is outp

gold – manual page for gold (GNU Binutils for Debian 2.21.51.20110421) 1.11

FIXME .







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