Help with test statement Post: 302482614

7 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Using grep in a test/if statement

Okay, well this is more or less my first attempt at writing a shell script. Anyways, here's my code: cd ${PATH} if then rm ${FILE} ./anotherScript else exit 1 fi exit 1 Anyways, it's a pretty simple script that is supposed to search for the...

2. UNIX for Dummies Questions & Answers

if test statement

Can you use an if statement after an else? example if then echo "word" else if then echo "word"

3. Shell Programming and Scripting

Test on string containing spacewhile test 1 -eq 1 do read a $a if test $a = quitC then break fi d

This is the code: while test 1 -eq 1 do read a $a if test $a = stop then break fi done I read a command on every loop an execute it. I check if the string equals the word stop to end the loop,but it say that I gave too many arguments to test. For example echo hello. Now the...

4. Shell Programming and Scripting

Perl - automating if statement test

Hello all, I'm trying to automate an if statement in my Perl script. The script opens an input file for reading, checks each line in the file for a particular substring, and if it finds the substring, writes it to an output file. There are approximately 200 different input files. Each has...

5. Shell Programming and Scripting

How to check weather a string is like test* or test* ot test in if condition

How to check weather a string is like test* or test* ot *test* in if condition

6. Shell Programming and Scripting

string test in IF statement

How do I test multiple words in a string test like below: if ] then print "You entered $TBS name.\n" else print "You entered an incorrect response.\n" fi This test does not work. I have tried different syntax versions. How does this work? And is there a better way to do it? ...

7. Shell Programming and Scripting

If statement test against number range [0-9]

Is it possible to test against a varible within a ranges in a if statement. ex. if ];then echo "not in range" else echo "number within range" fi

LEARN ABOUT POSIX

sample

Packet sample action in tc(8)					       Linux					     Packet sample action in tc(8)

NAME

       sample - packet sampling tc action

SYNOPSIS

       tc ... action sample rate RATE group GROUP [ trunc SIZE ] [ index INDEX ]

       tc ... action sample index INDEX

DESCRIPTION

       The sample action allows sampling packets matching classifier.

       The  packets  are  chosen randomly according to the rate parameter, and are sampled using the psample generic netlink channel. The user can
       also specify packet truncation to save user-kernel traffic. Each sample includes some informative metadata about the original packet, which
       is sent using netlink attributes, alongside the original packet data.

       The  user  can either specify the sample action parameters as presented in the first form above, or use an existing sample action using its
       index, as presented in the second form.

SAMPLED PACKETS METADATA FIELDS

       The metadata are delivered to userspace applications using the psample generic netlink channel, where each sample  includes  the  following
       netlink attributes:

       PSAMPLE_ATTR_IIFINDEX
	      The input interface index of the packet, if there is one.

       PSAMPLE_ATTR_OIFINDEX
	      The output interface index of the packet. This field is not relevant on ingress sampling

       PSAMPLE_ATTR_ORIGSIZE
	      The size of the original packet (before truncation)

       PSAMPLE_ATTR_SAMPLE_GROUP
	      The psample group the packet was sent to

       PSAMPLE_ATTR_GROUP_SEQ
	      A sequence number of the sampled packet. This number is incremented with each sampled packet of the current psample group

       PSAMPLE_ATTR_SAMPLE_RATE
	      The rate the packet was sampled with

OPTIONS

       rate RATE
	      The packet sample rate.  RATE is the expected ratio between observed packets and sampled packets. For example, RATE of 100 will lead
	      to an average of one sampled packet out of every 100 observed.

       trunc SIZE
	      Upon set, defines the maximum size of the sampled packets, and causes truncation if needed

       group GROUP
	      The psample group the packet will be sent to. The psample module defines the concept of groups, which allows the user to match  spe-
	      cific sampled packets in the case of multiple sampling rules, thus identify only the packets that came from a specific rule.

       index INDEX
	      Is  a  unique  ID  for  an  action. When creating new action instance, this parameter allows to set the new action index. When using
	      existing action, this parameter allows to specify the existing action index.  The index must 32bit  unsigned  integer  greater  than
	      zero.

EXAMPLES

       Sample one of every 100 packets flowing into interface eth0 to psample group 12:

	      tc qdisc add dev eth0 handle ffff: ingress
	      tc filter add dev eth0 parent ffff: matchall 
		   action sample rate 100 group 12 index 19

       Use the same action instance to sample eth1 too:

	      tc qdisc add dev eth1 handle ffff: ingress
	      tc filter add dev eth1 parent ffff: matchall 
		   action sample index 19

SEE ALSO

       tc(8), tc-matchall(8) psample(1)

iproute2							    31 Jan 2017 				     Packet sample action in tc(8)