Assign variable in bash script
$ d=$(date)
$ echo $d
Fri 18 Oct 2019 04:31:03 PM CST
However,when it come to ipython terminal,
In [25]: !d=$(date)
In [26]: !echo $d
In [27]:
What's the problem?
I'm not sure what you mean by "magic method".
If you want to run a bash command in your Jupyter/iPython notebook, you can use Python's subprocess module. In this case the following should work:
import subprocess
d = subprocess.Popen('date', stdout=subprocess.PIPE)
d = d.communicate()[0]
I think what you're looking for is this:
d=!date
d
or
d=!date
print(d)
it returns a list:
['lun 16 nov 2020 13:13:24 CET']
if you just want the string, try:
d[0]
Related
I'm new to KDB and I'm looking at it from a security stand point.
Can I run a combination of a DB query and an OS command as a one liner?
Or, can I store the OS command's output to a DB object?
I've been playing around with KDB Q, but either it's not possible or
I haven't found the proper syntax.
Thank you
Yes, see below:
q)update res:system each cmd from ([] cmd:("uptime";"date";"uname -a"))
cmd res
----------------------------------------------------------------------------------------------------------------------
"uptime" " 21:01:03 up 31 days, 6:54, 8 users, load average: 0.00, 0.03, 0.00"
"date" "Fri 17 Mar 21:01:03 GMT 2017"
"uname -a" "Linux glyph01 4.4.0-62-generic #83-Ubuntu SMP Wed Jan 18 14:10:15 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux"
Running a system command is more or less the same as running any other function in Kdb+.
I'm trying to get an Erlang function to execute a bash command containing unicode characters. For example, I want to execute the equivalent of:
touch /home/jani/ჟანიweł
I put that command in variable D, for example:
io:fwrite("~ts", [list_to_binary(D)]).
touch /home/jani/ჟანიwełok
but after I execute:
os:cmd(D)
I get file called á??á??á??á??weÅ?. How can I fix it?
os:cmd(binary_to_list(unicode:characters_to_binary("touch /home/jani/编程"))).
Executing this command creates a file named ��, while executing the equivalent touch command directly in a terminal creates the file with the correct name.
Its because Erlang reads your source files like latin1 by default, but on newer versions of erlang you can set your files to use unicode.
%% coding: utf-8
-module(test).
-compile(export_all).
test() ->
COMMAND = "touch ჟანიweł",
os:cmd(COMMAND).
and then compiling and executing the module works fine
rorra-air:~ > erl
Erlang/OTP 17 [erts-6.4] [source] [64-bit] [smp:4:4] [async-threads:10] [hipe] [kernel-poll:false] [dtrace]
Eshell V6.4 (abort with ^G)
1> c(test).
{ok,test}
2> test:test().
[]
and it created the file on my filesystem
rorra-air:~ > ls -lta
total 144
-rw-r--r-- 1 rorra staff 0 Jun 9 15:18 ჟანიweł
Consider a simple attempt at shell expansion:
Simple/direct approach :
scala> ("/bin/ls /tmp/*" run BasicIO(false, sb, None)).exitValue
ls: /tmp/*: No such file or directory
res18: Int = 1
I have tried a number of combinations of ProcessIO, BasicIO, Process, etc and can not figure out how to get shell expansion to work.
bash -c :
scala> ("bash -c \"/bin/ls /tmp/*\"" run BasicIO(false, sb, None)).exitValue
/tmp/*": -c: line 0: unexpected EOF while looking for matching `"'
/tmp/*": -c: line 1: syntax error: unexpected end of file
res19: Int = 2
Pipe to bash -s :
scala> ("echo \"/bin/ls /tmp/*\" | bash -s") run BasicIO(false, sb, None)).exitValue
<console>:1: error: ';' expected but ')' found.
("echo \"/bin/ls /tmp/*\" | bash -s") run BasicIO(false, sb, None)).exitValue
btw that last one in shell looks like the following (and works):
21:28:32/dstat $echo "/bin/ls /tmp/*" | bash -s
/tmp/OSL_PIPE_501_SingleOfficeIPC_a974a3af70d46eaeed927022833718b7
/tmp/oobelib.log
/tmp/spark-steve-org.apache.spark.deploy.master.Master-1.pid
/tmp/spark-steve-org.apache.spark.deploy.worker.Worker-1.pid
/tmp/KSOutOfProcessFetcher.501.qQkpPp2uZLdVc5pukHmfJMR4bkM=:
Shell escaping would also be of interest to understand wrt scala Process classes: an example including both expansion and escaping would be optimal.
UPDATE I found this JIRA - it may be relevant. I hope not - that means there were little/no hope for the functionality described here..
sys.process._ is so restrictive in what it can accept that is not usable https://issues.scala-lang.org/browse/SI-7027
Another update I found an old email thread involving the esteemed Daniel Sobral who mentions:
Because the quotes are not delimiting the parameter passed to bash --
it is Scala who decides how the arguments break up, and it simply
splits on spaces, without any quotation facility. If you try the
following, instead, it will work:
Seq("bash", "-c", "ls *.scala").!
It is looking ever more grim for a "fire and forget" version of running a shell command. I yearn for the ruby
%x{whatever shell string you want goes here}
e.g.
echo 'print %x{ls -lrtad /etc/* 2>&1}' | ruby
Which most satisfyingly returns:
-r--r--r-- 1 root wheel 69836 May 28 2013 /etc/php.ini.default-
5.2-previous~orig
lrwxr-xr-x 1 root wheel 30 Oct 22 2013 /etc/localtime -> /usr/share/zoneinfo/US/Pacific
-rw-r--r-- 1 root wheel 102 Nov 5 2013 /etc/hostconfig
-rw-r--r-- 1 root wheel 1286 Nov 5 2013 /etc/my.cnf
-rw-r--r-- 1 root wheel 4161 Dec 18 2013 /etc/sshd_config~previous
-rw-r--r-- 1 root wheel 199 Feb 7 2014 /etc/shells
-rw-r--r-- 1 root wheel 0 Sep 9 2014 /etc/xtab
-rw-r--r-- 1 root wheel 1316 Sep 9 2014 /etc/ttys
.. etc
but looks like that were not happening with Scala..
I fear you took my answer the wrong way. Ruby is doing the same thing, and I know this without looking at their code because what Java (and, by extension, Scala) presents as API is a direct translation of the Unix API.
It is shell that does shell expansions, and while it's perfectly possible for any other software to emulate them, it would be a losing game. Wildcards are often provided, but they are a small part of shell expansion.
My answer has everything you need, but let me expand on that:
import scala.sys.process._
implicit class RubyX(val sc: StringContext) extends AnyVal {
def x(args: Any*): ProcessBuilder = {
val strings = sc.parts.iterator
val expressions = args.iterator
var buf = new StringBuffer(strings.next)
while(strings.hasNext) {
buf append expressions.next
buf append strings.next
}
Process(Seq("bash", "-c", buf.toString))
}
}
then you can do
x"ls *.scala".!
I returned a ProcessBuilder, so you can pick whatever is the best form of execution for you, such as ! above that returns the exit code and echoes everything else to stdout.
I'm running a JMeter test plan from command line and it's currently outputting something along the lines of:
Created the tree successfully using C:\*****\TestPlan.jmx
Starting the test # Thu Oct 11 10:20:43 EDT 2012 (1349965243947)
Waiting for possible shutdown message on port 4445
Tidying up ... # Thu Oct 11 10:20:46 EDT 2012 (1349965246384)
... end of run
Is there any way to turn off this output and have the plan execute 'silently'?
Found a way to do this, by following this article http://www.robvanderwoude.com/battech_redirection.php
and appending > NUL to the command
jmeter -n -t C:\***\TestPlan.jmx -Jhostname=%1 > NUL
I followed some online guides trying to get some headless VMs to start/suspend automatically at boot/shutdown on my Mac. I can't get it to work at all. This is my first time trying to get script runs on Startup/Shutdown, so it could be that I'm just missing something very basic and if that's the case I apologize.
These are the steps I followed:
Created a directory /Library/StartupItems/HeadlessVM
Created two files within that directory:
-rwxr--r-- 1 root wheel 242 Feb 19 19:05 HeadlessVM
-rw-r--r-- 1 root wheel 188 Feb 20 12:42 StartupParameters.plist
Contents for HeadlessVM
$ cat HeadlessVM
#!/bin/sh
. /etc/rc.common
StartService ()
{
ConsoleMessage "Starting HeadlessVM"
/usr/local/bin/runvmheadless
}
StopService ()
{
ConsoleMessage "Suspending HeadlessVM"
/usr/local/bin/suspendvmheadless
}
RunService "$1"
Contents for StartupParameters.plist
$ cat StartupParameters.plist
{
Description = "Runs/Suspends Virtual Machine Headless on OS X Startup/Shutdown";
Provides = ("HeadlessVM");
Uses = ("Disks");
OrderPreference = ("Late");
}
Created my script files, that will perform both actions:
-rwxr-xr-x# 1 xxxxxxx admin 164 Feb 19 01:06 runvmheadless
-rwxr-xr-x# 1 xxxxxxx admin 160 Feb 19 01:19 suspendvmheadless
Contents for runvmheadless
$ cat runvmheadless
#!/bin/bash
"/Applications/VMware Fusion.app/Contents/Library/vmrun" -T fusion start "/Volumes/Archive/Virtual Machines/vm.vmwarevm/vm.vmx" nogui
Contents for suspendvmheadless
$ cat suspendvmheadless
#!/bin/bash
"/Applications/VMware Fusion.app/Contents/Library/vmrun" -T fusion suspend "/Volumes/StaticData/Virtual Machines/vm.vmwarevm/vm.vmx"
My troubleshooting so far:
If I run the scripts from the terminal, they work as intended.
If I run sudo /sbin/SystemStarter (start or stop) "HeadlessVM" it also works.
On console I only see the following when I reboot, no clue on what's wrong tho.
2/20/12 12:11:09.128 PM SystemStarter: Runs/Suspends Virtual Machine Headless on OS X Startup/Shutdown (100) did not complete successfully
Appreciate any help, Thank you.
I found what was wrong. The code above is fine, the problem is that my scripts are trying to get data from an encrypted secondary disk which was not available at boot time.
I used this in order to bypass this problem:https://github.com/jridgewell/Unlock
Thanks