What is the significance of -- in the command line of commands like lxc-create or lxc-start.
I tried to use Google in order to get an answer but without success.
// Example 1
lxc-create -t download -n u1 -- -d ubuntu -r DISTRO-SHORT-CODENAME -a amd64
// Example 1
application="/root/app.out"
start="/root/lxc-app/lxc-start"
$start -n LXC_app -d -f /etc/lxc/lxc-app/lxc-app.conf -- $application &
As explained in the references provided in the comments, the "--" indicates the end of the options passed to the command. The following parameters/options will be eventually used by a sub-command called by the command.
In your example:
lxc-create -t download -n u1 -- -d ubuntu -r DISTRO-SHORT-CODENAME -a amd64
lxc-create command will interpret "-t download -n u1" and the remaining "-d ubuntu -r DISTRO-SHORT-CODENAME -a amd64" will be passed to the template script which will configure/populate the container.
In this specific example, the "-t download" makes lxc-create run a template script named something like "/usr/share/lxc/templates/lxc-download" to which it will pass "-d ubuntu -r DISTRO-SHORT-CODENAME -a amd64".
I am trying to load a specific tool ( nvm ) from within sh.
Installing it as explained in the page for bash it works perfectly and testing it returns the following.
$ bash
$ nvm --version
+ X.XX.X
but if I type
$ sh
$ nvm --version
+ sh: 1: nvm: not found
but still its expected as the default installation modifies the .bashrc.
now i have included the same .bashrc code in my /etc/profile
export NVM_DIR="/opt/nvm"
[ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
and tried again.
$ sh
$ nvm --version
+ sh: 1: nvm: not found
$ echo $NVM_DIR
+ /dir/to/nvm
$ [ -s "$NVM_DIR/nvm.sh" ] && echo "it works?"
+ it works?
$ [ -s "$NVM_DIR/nvm.sh" ] && . "$NVM_DIR/nvm.sh"
$ nvm --version
X.XX.X
which got me extremely confused. What exactly is happening ? Isn't sh loading the /etc/profile or am I doing something really wrong?
--edit after comments--
also tried to include it in the local profile
$ cat ~/.profile
+ export NVM_DIR="/opt/nvm"
+ [ -s "$NVM_DIR/nvm.sh" ] && \. "$NVM_DIR/nvm.sh"
$ sh
$ nvm --version
+ sh: 1: nvm: not found
The problem was described in this article with the sh blue line.
The solution to the problem was to set the /etc/profile/ in the ENV variable.
for example ENV=/etc/profile sh would load the profile when the sh opens. That solved the problem
I have the below command
su - root -s /usr/bin/sh -c "java -version|grep build"
But the pipe to grep doesn't seem to work since it prints all lines regardless
java -version writes to standard error, not standard output.
su - root -s /usr/bin/sh -c "java -version 2>&1 |grep build"
2>&1 copies standard error to standard output, so that it gets fed through the pipe and into grep.
That said, grep doesn't have to be run as root, assuming the pipeline isn't being specified for use by something that just runs arbitrary code using su sh -c '...'.
su - root -s /usr/bin/sh -c 'java -version' 2>&1 | grep build
I'm trying to execute this code:
sudo su sh <(curl https://mirror.cyberpanel.net/install-test.sh || wget -O - https://mirror.cyberpanel.net/install-test.sh)
but get this output:
...
su: user sh does not exist
....
curl: (23) Failed writing body (0 != 8192)
.....
Cannot write to ‘-’ (Success).
Can anyone help resolve?
In the command su sh sh is a user name. If you want su to interpret it as a command to run add option -c:
sudo su -c "sh…"
See https://linux.die.net/man/1/su and https://www.sudo.ws/man.html
Save the file to disk first
url=https://mirror.cyberpanel.net/install-test.sh
curl -O "$url" || wget -O - "$url"
# Examine the contents of install-test.sh first, *then* run ...
sudo sh install-test.sh
"Examine" could me reading it yourself to verify that it doesn't do anything you don't want it to do, or comparing its MD5 checksum to an expected value.
When using inline C with Varnish I've not been able to get /etc/varnish/default
to be happy at startup.
I've tested inline C with varnish for two things: GeoIP detection and Anti-Site-Scraping functions.
The DAEMON_OPTS always complains even though I'm following what other seem
to indicate works fine.
My problem is that this command line start up works:
varnishd -f /etc/varnish/varnish-default.conf -s file,/var/lib/varnish/varnish_storage.bin,512M -T 127.0.0.1:2000 -a 0.0.0.0:8080 -p 'cc_command=exec cc -fpic -shared -Wl,-x -L/usr/include/libmemcached/memcached.h -lmemcached -o %o %s'
But it errors out with trying to start up from default start scripts:
/etc/default/varnish has this in it:
DAEMON_OPTS="-a :8080 \
-T localhost:2000 \
-f /etc/varnish/varnish-default.conf \
-s file,/var/lib/varnish/varnish_storage.bin,512M \
-p 'cc_command=exec cc -fpic -shared -Wl,-x -L/usr/include/libmemcached/memcached.h -lmemcached -o %o %s'"
The error is:
# /etc/init.d/varnish start
Starting HTTP accelerator: varnishd failed!
storage_file: filename: /var/lib/varnish/vbox.local/varnish_storage.bin size 512 MB.
Error:
Unknown parameter "'cc_command".
If I try change the last line to:
-p cc_command='exec cc -fpic -shared -Wl,-x -L/usr/include/libmemcached/memcached.h -lmemcached -o %o %s'"
It's error is now:
# /etc/init.d/varnish start
Starting HTTP accelerator: varnishd failed!
storage_file: filename: /var/lib/varnish/vbox.local/varnish_storage.bin size 512 MB.
Error: Unknown storage method "hared"
It's trying to interpret the '-shared' as -s hared and 'hared' is not a storage type.
For both GeoIP and the Anti-Site-Scrape I've used the exact recommended daemon options
plus have tried all sorts of variations like adding ' and '' but no joy.
Here is a link to the instruction I've followed that work fine except the DAEMON_OPTS part.
http://drcarter.info/2010/04/how-fighting-against-scraping-using-varnish-vcl-inline-c-memcached/
I'm using Debian and the exact DAEMON_OPTS as stated in the instructions.
Can anyone help with a pointer on what's going wrong here?
Even if Jacob will probably never read this, visitors from the future might appreciate what I'm going to write.
I believe I know what's wrong, and it looks like a Debian-specific problem, at least verified on Ubuntu 11.04 and Debian Squeeze.
I traced the execution from my /etc/default/varnish that contains the $DAEMON_OPTS to the init script.
In the init script /etc/init.d/varnish, the start_varnishd() function is:
start_varnishd() {
log_daemon_msg "Starting $DESC" "$NAME"
output=$(/bin/tempfile -s.varnish)
if start-stop-daemon \
--start --quiet --pidfile ${PIDFILE} --exec ${DAEMON} -- \
-P ${PIDFILE} ${DAEMON_OPTS} > ${output} 2>&1; then
log_end_msg 0
else
log_end_msg 1
cat $output
exit 1
fi
rm $output
}
So I modified it to print the full start-stop-daemon command line, like:
start_varnishd() {
log_daemon_msg "Starting $DESC" "$NAME"
output=$(/bin/tempfile -s.varnish)
+ echo "start-stop-daemon --start --quiet --pidfile ${PIDFILE} --exec ${DAEMON} -- -P ${PIDFILE} ${DAEMON_OPTS} > ${output} 2>&1"
if start-stop-daemon \
--start --quiet --pidfile ${PIDFILE} --exec ${DAEMON} -- \
-P ${PIDFILE} ${DAEMON_OPTS} > ${output} 2>&1; then
log_end_msg 0
So I got a command line echoed on STDOUT, and copied-pasted it into my shell. And, surprise! It worked. WTF?
Repeated again to be sure. Yes, it works. Mmh. Could it be another of those bash/dash corner cases?
Let's try feeding the start-stop-daemon command line to bash, and see how it reacts:
start_varnishd() {
log_daemon_msg "Starting $DESC" "$NAME"
output=$(/bin/tempfile -s.varnish)
if bash -c "start-stop-daemon \
--start --quiet --pidfile ${PIDFILE} --exec ${DAEMON} -- \
-P ${PIDFILE} ${DAEMON_OPTS} > ${output} 2>&1"; then
log_end_msg 0
else
log_end_msg 1
cat $output
exit 1
fi
rm $output
}
Yes, it works just fine, at least for my case.
Here's the relevant part of my /etc/default/varnish:
...
## Alternative 2, Configuration with VCL
#
# Listen on port 6081, administration on localhost:6082, and forward to
# one content server selected by the vcl file, based on the request. Use a 1GB
# fixed-size cache file.
#
DAEMON_OPTS="-a :6081 \
-T localhost:6082 \
-f /etc/varnish/geoip-example.vcl \
-S /etc/varnish/secret \
-s malloc,100M \
-p 'cc_command=exec cc -fpic -shared -Wl,-x -L/usr/include/GeoIP.h -lGeoIP -o %o %s'"
...
I've seen posts where someone tried to work around this problem by moving the compile command into a separated shell script. Unfortunately that doesn't change the fact that start-stop-daemon is going to pass the $DAEMON_OPTS var through dash, and that will result in mangled options.
Would be something along the lines of:
-p 'cc_command=exec /etc/varnish/compile.sh %o %s'"
And then the compile.sh script as:
#!/bin/sh
cc -fpic -shared -Wl,-x -L/usr/include/GeoIP.h -lGeoIP -o $#
but it doesn't work, so just patch your init scripts, and you're good to go!
Hope you can find this information useful.
You can try using :-
DAEMON_OPTS="-a :8080 \
-T localhost:2000 \
-f /etc/varnish/varnish-default.conf \
-s file,/var/lib/varnish/varnish_storage.bin,512M \
-p cc_command='exec cc -fpic -shared -Wl,-x -L/usr/include/libmemcached/memcached.h -lmemcached -o %o %s'"
Obviously, your startup script interpreting the DAEMON_OPTS is not prepared for whitespace (even within single quotes). At my Fedora (15) installation, the suggested solution works fine; the arguments get interpreted correctly because the "$*" bash parameter is passed in /etc/init.d/varnish and in /etc/init.d/functions in daemon().
Did you get your startup scripts from a package or did you make custom scripts?
This isn't directly related to the question, but you may find yourself here if you are working through the Varnish Tutorial - Put Varnish on port 80.
For recent installs of Varnish on Debian systems the configuration for varnishd startup options can be found in /etc/systemd/system/multi-user.target.wants/varnish.service. The documented way of changing the port via /etc/default/varnish still exists, but is no longer functional unless you change your system to use init scripts rather than systemd.
After you've changed your options in /etc/systemd/system/multi-user.target.wants/varnish.service, don't forget to run systemctl daemon-reload, which will catalog the changes for executing the program.