Unix command redirection Post: 302139415

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

redirection in unix, '<' as opposed to '>'

Greetings, When directing in unix, symbol > means saving. E.g. I can save ls command output into mama like this: ls -f > mama Could someone give me a real example of how the opposite, i.e. symbol < is used?. Could not find its counterpart in Windows (I seem to learn better when i see...

2. UNIX for Dummies Questions & Answers

Unix redirection to '&-'

Hi UF family members, I am intermediate in Unix language and scripting.I know the redirection systems in unix,but the below statement confuses me: #!/bin/ksh . $HOME/.profile 2>&- Actually this is an extract from a unix script which was trying to set the...

3. Programming

Java with Unix (Redirection + Piping)

Hi, To explain this question I will have to go into a bit of detail. I hope you don't mind. currently I have a log handler (an already compiled c++ version) and what it does is makes a log file and writes all the unix output (echo, etc) of a script to that log file. To me the log_handler is...

4. Shell Programming and Scripting

echo command and file I/O Redirection

I have a colon-delimited text file of names, addresses and phone numbers. I am trying to write a script that can add additional entries and then sort it alphabetical by last name and resave it to the original file. I am using C shell to script. This is the section of my script that I wish to...

5. Shell Programming and Scripting

nohup command o/p redirection

Hi I am using nohup command in script(say nohup ls- ltr > somefile 2>&1 & ). I dont want any kind of output to be displayed on screen. When i tried the above nohup it still gives me some out put on screen like 2991 Done >somefile 2>&1 Please you let me know what is...

6. Shell Programming and Scripting

Unix shell output redirection help

Hi all, Actually i need to know whether there is any way to redirect the output of shell operations into any file without pipe . Actually my problem is , i run some command & its result is displayed on shell after some calculations on shell, so if i redirect its output to file, it is not...

7. Shell Programming and Scripting

redirection if command help please

#!/bin/bash clear echo "Hello $USER" echo "Do you wish to run this network configuration script ?" read option if($option == 'Y' || 'y' ) then echo " auto eth0 iface eth0 inet static address 192.168.1.161 ...

8. UNIX for Dummies Questions & Answers

redirection in unix

how to redirect a output value to a file

9. UNIX and Linux Applications

output redirection command

Dear All, ./waf --run scratch/myfirst > log.out 2>&1 The above is a command line to redirect the output to a file called log.out. what is the 2>&1 part for ? Thank you

10. UNIX for Dummies Questions & Answers

Redirection of file input to command

Hello, I'm new to Unix (working with OS X 10.8.5) and therefore at the beginning of my adventure. If I ask something stupid, then this is not intentional, but simple nescience. :rolleyes: I have a problem with the redirection of text file content to echo. I was experimenting with redirection...

LEARN ABOUT MOJAVE

tc-mirred

Mirror/redirect action in tc(8)                                        Linux                                       Mirror/redirect action in tc(8)

NAME

       mirred - mirror/redirect action

SYNOPSIS

       tc ... action mirred DIRECTION ACTION [ index INDEX ] dev DEVICENAME

       DIRECTION := { ingress | egress }

       ACTION := { mirror | redirect }

DESCRIPTION

       The  mirred  action  allows  packet  mirroring  (copying)  or redirecting (stealing) the packet it receives. Mirroring is what is sometimes
       referred to as Switch Port Analyzer (SPAN) and is commonly used to analyze and/or debug flows.

OPTIONS

       ingress
       egress Specify the direction in which the packet shall appear on the destination interface.

       mirror
       redirect
              Define whether the packet should be copied (mirror) or moved (redirect) to the destination interface.

       index INDEX
              Assign a unique ID to this action instead of letting the kernel choose one automatically.  INDEX is a 32bit unsigned integer greater
              than zero.

       dev DEVICENAME
              Specify the network interface to redirect or mirror to.

EXAMPLES

       Limit ingress bandwidth on eth0 to 1mbit/s, redirect exceeding traffic to lo for debugging purposes:

              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: u32 
                   match u32 0 0 
                   action police rate 1mbit burst 100k conform-exceed pipe 
                   action mirred egress redirect dev lo

       Mirror all incoming ICMP packets on eth0 to a dummy interface for examination with e.g. tcpdump:

              # ip link add dummy0 type dummy
              # ip link set dummy0 up
              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: protocol ip 
                   u32 match ip protocol 1 0xff 
                   action mirred egress mirror dev dummy0

       Using an ifb interface, it is possible to send ingress traffic through an instance of sfq:

              # modprobe ifb
              # ip link set ifb0 up
              # tc qdisc add dev ifb0 root sfq
              # tc qdisc add dev eth0 handle ffff: ingress
              # tc filter add dev eth0 parent ffff: u32 
                   match u32 0 0 
                   action mirred egress redirect dev ifb0

SEE ALSO

       tc(8), tc-u32(8)

iproute2                                                            11 Jan 2015                                    Mirror/redirect action in tc(8)

10 More Discussions You Might Find Interesting

1. UNIX for Dummies Questions & Answers

redirection in unix, '<' as opposed to '>'

Discussion started by: alikun

2. UNIX for Dummies Questions & Answers

Unix redirection to '&-'

Discussion started by: DILEEP410

3. Programming

Java with Unix (Redirection + Piping)

Discussion started by: fluke_perf

4. Shell Programming and Scripting

echo command and file I/O Redirection

Discussion started by: userix