I have a telnet command which prints hundreds of lines of output, Can I grep the output?
Use the 'script' command. If you run 'script ' before running telnet, all text that gets written to the terminal also gets written to /file/path/filename. You'll have to do 'exit' or Ctrl-D to actually write to the file or you can keep a check on the file.
Finally grep on the file using filename | grep "search text"
/file/path/filename is the path where you want to store the output of telnet.
Using script command
script /tmp/myscript.txt
then all the commands you fire in terminal and the output will go in this file.
use ctrl + D when you are done, which will write to the file.
Do a grep on this file.
cat /tmp/myscript.txt | grep "textToSearch"
Use tee command to redirect the content to file:
telnet google.com 80 | tee outfile
Then grep the file
To grep output from the network connection, you can use Bash shell instead of telnet, e.g.:
exec {stream}<>/dev/tcp/example.com/80
printf "GET / HTTP/1.1\nHost: example.com\nConnection: close\n\n" >&${stream}
grep Example <&${stream}
Related
I'm developping a script to search for patterns within scripts executed from CRON on a bunch of remote servers through SSH.
Script on client machine -- SSH --> Remote Servers CRON/Scripts
For now I can't get the correct output.
Script on client machine
#!/bin/bash
server_list=( '172.x.x.x' '172.x.x.y' '172.x.x.z' )
for s in ${server_list[#]}; do
ssh -i /home/user/.ssh/my_key.rsa user#${s} crontab -l | grep -v '^#\|^[[:space:]]*$' | cut -d ' ' -f 6- | awk '{print $1}' | grep -v '^$\|^echo\|^find\|^PATH\|^/usr/bin\|^/bin/' | xargs -0 grep -in 'server.tld\|10.x.x.x'
done
This only gives me the paths of scripts from crontab, not the matched lines and line number plus the first line is prefixed with "grep:" keyword (example below):
grep: /opt/directory/script1.sh
/opt/directory/script2.sh
/opt/directory/script3.sh
/opt/directory/script4.sh
How to get proper output, meaning the script path plus line number plus line of matching pattern?
Remote CRON examples
OO 6 * * * /opt/directory/script1.sh foo
30 6 * * * /opt/directory/script2.sh bar
Remote script content examples
1 ) This will match grep pattern
#!/bin/bash
ping -c 4 server.tld && echo "server.tld ($1)"
2 ) This won't match grep pattern
#!/bin/bash
ping -c 4 8.x.x.x && echo "8.x.x.x ($1)"
Without example input, it's really hard to see what your script is attempting to do. But the cron parsing could almost certainly be simplified tremendously by refactoring all of it into a single Awk script. Here is a quick stab, with obviously no way to test.
#!/bin/sh
# No longer using an array for no good reason, so /bin/sh will work
for s in 172.x.x.x 172.x.x.y 172.x.x.z; do
ssh -i /home/user/.ssh/my_key.rsa "user#${s}" crontab -l |
awk '! /^#|^[[:space:]]*$/ && $6 !~ /^$|^(echo|find|PATH|\/usr\/bin|\/bin\/)/ { print $6 }' |
# no -0; use grep -E and properly quote literal dot
xargs grep -Ein 'server\.tld|10.x.x.x'
done
Your command would not output null-delimited data to xargs so probably the immediate problem was that xargs -0 would receive all the file names as a single file name which obviously does not exist, and you forgot to include the ": file not found" from the end of the error message.
The use of grep -E is a minor hack to enable a more modern regex syntax which is more similar to that in Awk, where you don't have to backslash the "or" pipe etc.
This script, like your original, runs grep on the local system where you run the SSH script. If you want to run the commands on the remote server, you will need to refactor to put the entire pipeline in single quotes or a here document:
for s in 172.x.x.x 172.x.x.y 172.x.x.z; do
ssh -i /home/user/.ssh/my_key.rsa "user#${s}" <<\________HERE
crontab -l |
awk '! /^#|^[[:space:]]*$/ && $6 !~ /^$|^(echo|find|PATH|\/usr\/bin|\/bin\/)/ { print $6 }' |
xargs grep -Ein 'server\.tld|10.x.x.x'
________HERE
done
The refactored script contains enough complexities in the quoting that you probably don't want to pass it as an argument to ssh, which requires you to figure out how to quote strings both locally and remotely. It's easier then to pass it as standard input, which obviously just gets transmitted verbatim.
If you get "Pseudo-terminal will not be allocated because stdin is not a terminal.", try using ssh -t. Sometimes you need to add multiple -t options to completely get rid of this message.
I write down some commands row by row in a file, and I want to execute the commands through grep and pipe;
for example:
1.there is a file a.txt,which content is like below:
echo "hello world"
ls -l
2.then I want execute the first line in my terminal, so I want it like this:
cat a.txt | grep echo | execute the output of previous commands
so that, I can finally execute the command, which is the first line of a.txt.
(can not find any answer of this, so I come here to find some help.)
You can either pipe the command to bash (or any other shell) to execute it:
sed -n 1p a.txt | bash
or you can use eval with command substitution:
eval $(head -n1 a.txt)
BTW, I showed you another two ways how to extract the line from the file.
I'm trying to use grep in a machine but it just isn't working. When I use it after a pipeline (for example ps -aux | grep grep) it works (in the example showing grep processes).
But I'm trying for search a word into files but it just starts at S+ () state, no matter if I write "grep anything", "grep -Ril anything", etc.
From the man page:
grep searches the named input FILEs (or standard input if no files are named ...
So when you run grep anything, grep is waiting for standard input. You need to give it either filenames on the command line, or input via stdin.
I would like to use tee to append to multiple files, however, I don't need it to print to my shell, just the files. Outputting to /dev/null works great, as the command still appends to the files, and doesn't print to the shell:
echo test | tee -a file1 file2 file3 &>/dev/null
I was just wondering if this is the proper way to do it, as tee --help doesn't seem to have a parameter to not print to shell:
-a, --append append to the given FILEs, do not overwrite
-i, --ignore-interrupts ignore interrupt signals
-p diagnose errors writing to non pipes
--output-error[=MODE] set behavior on write error. See MODE below
--help display this help and exit
--version output version information and exit
I'm pretty sure this is the right way to do it, I guess I would just like some confirmation.
Well okay then...
... | tee -a file1 file2 >> file3
I'm running a command to retrieve the location of a logfile using from a .sh bash script
rig=`forever list | grep 'server.*root.*\.log' | awk '{print $8}'`
echoing it prints:
echo $rig
/root/.forever/1cFY.log
But when I try to read the file (which exists) like so:
less $rig
I get:
/root/.forever/1cFY.log: No such file or directory
However if I manually enter the file name without my .sh script it works.
Any ideas?
Looks like you have grep configured to output color. Just drop the grep and use awk:
rig=$(forever list | awk '/server.*root.*\.log/{print $8}')