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How to send literal string over TCP (netcat/socat-like), but provided by command arguments?
socat reliable file transfer over TCPLinux Shell Script - Send command over TCP to Sharp AquosCommand line streaming string manipulation from netcatHow to record an interactice socat TCP/TLS session?Expose awk over tcp (inetd, socat, etc.)Using socat to Tunnel/Proxy TCP want to split send/receive into separate filesCreate UDP to TCP bridge with socat/netcat to relay control commands for vlc media-playerWhich layer(IP/TCP?) is netcat/socat working on?Can I resume a failed (ZoL) ZFS send over netcat?socat - UNIX-LISTEN and TCP-LISTEN in one command
If I want to send a string over TCP in a shell environment, I can do something like:
echo text | nc 1.2.3.4 9876
Cool. Interactively, that works. Now I want to do this programmatically by spawning a subprocess from another program, so I want to avoid using a shell and pipes.
Also, since I'm deploying with distroless Docker containers, they don't come with a shell.
Is there an existing tool to send an command argument as string over TCP? I'm looking for an (imaginary) variant of nc, e.g.:
nc 1.2.3.4 9876 text
that does the same as
echo text | nc 1.2.3.4 9876
(Need the output too.)
I'm about to write my own application for this, but I can imagine this exists already, simply taking one of the argv instead of stdin to pass on.
Looked at socat, which can read from files with OPEN, which is very close to what I want, but I need the string to be passed as parameter from the command issued.
For the full context, the entrypoint of the Docker container should be settable by it, without shells or other interpreted language, but pure OS native dependencies like glibc (like socat/nc is!).
tcp socket netcat socat
asked yesterday
gertvdijkgertvdijk
7,49252945
|
show 4 more comments
If I want to send a string over TCP in a shell environment, I can do something like:
echo text | nc 1.2.3.4 9876
Cool. Interactively, that works. Now I want to do this programmatically by spawning a subprocess from another program, so I want to avoid using a shell and pipes.
Also, since I'm deploying with distroless Docker containers, they don't come with a shell.
Is there an existing tool to send an command argument as string over TCP? I'm looking for an (imaginary) variant of nc, e.g.:
nc 1.2.3.4 9876 text
that does the same as
echo text | nc 1.2.3.4 9876
(Need the output too.)
I'm about to write my own application for this, but I can imagine this exists already, simply taking one of the argv instead of stdin to pass on.
Looked at socat, which can read from files with OPEN, which is very close to what I want, but I need the string to be passed as parameter from the command issued.
For the full context, the entrypoint of the Docker container should be settable by it, without shells or other interpreted language, but pure OS native dependencies like glibc (like socat/nc is!).
tcp socket netcat socat
asked yesterday
gertvdijkgertvdijk
7,49252945
2
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access tobusybox echoorbusybox catcommands ?
– Kiwy
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.ENTRYPOINT ["/bin/sh", "-c", "mycommand"]is unnecessary, just doENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g.man 2 execve.
– gertvdijk
yesterday
1
Please read your question you need to use|to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module toncto allow the use of a file as an argument. So if you have a busybox inside you can usebusybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.
– Kiwy
yesterday
2
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday
|
show 4 more comments
If I want to send a string over TCP in a shell environment, I can do something like:
echo text | nc 1.2.3.4 9876
Cool. Interactively, that works. Now I want to do this programmatically by spawning a subprocess from another program, so I want to avoid using a shell and pipes.
Also, since I'm deploying with distroless Docker containers, they don't come with a shell.
Is there an existing tool to send an command argument as string over TCP? I'm looking for an (imaginary) variant of nc, e.g.:
nc 1.2.3.4 9876 text
that does the same as
echo text | nc 1.2.3.4 9876
(Need the output too.)
I'm about to write my own application for this, but I can imagine this exists already, simply taking one of the argv instead of stdin to pass on.
Looked at socat, which can read from files with OPEN, which is very close to what I want, but I need the string to be passed as parameter from the command issued.
For the full context, the entrypoint of the Docker container should be settable by it, without shells or other interpreted language, but pure OS native dependencies like glibc (like socat/nc is!).
tcp socket netcat socat
asked yesterday
gertvdijkgertvdijk
7,49252945
If I want to send a string over TCP in a shell environment, I can do something like:
echo text | nc 1.2.3.4 9876
Cool. Interactively, that works. Now I want to do this programmatically by spawning a subprocess from another program, so I want to avoid using a shell and pipes.
Also, since I'm deploying with distroless Docker containers, they don't come with a shell.
Is there an existing tool to send an command argument as string over TCP? I'm looking for an (imaginary) variant of nc, e.g.:
nc 1.2.3.4 9876 text
that does the same as
echo text | nc 1.2.3.4 9876
(Need the output too.)
I'm about to write my own application for this, but I can imagine this exists already, simply taking one of the argv instead of stdin to pass on.
Looked at socat, which can read from files with OPEN, which is very close to what I want, but I need the string to be passed as parameter from the command issued.
For the full context, the entrypoint of the Docker container should be settable by it, without shells or other interpreted language, but pure OS native dependencies like glibc (like socat/nc is!).
tcp socket netcat socat
tcp socket netcat socat
asked yesterday
gertvdijkgertvdijk
7,49252945
asked yesterday
gertvdijkgertvdijk
7,49252945
edited yesterday
gertvdijk
asked yesterday
gertvdijkgertvdijk
7,49252945
asked yesterday
gertvdijkgertvdijk
7,49252945
asked yesterday
gertvdijkgertvdijk
7,49252945
7,49252945
2
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access tobusybox echoorbusybox catcommands ?
– Kiwy
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.ENTRYPOINT ["/bin/sh", "-c", "mycommand"]is unnecessary, just doENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g.man 2 execve.
– gertvdijk
yesterday
1
Please read your question you need to use|to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module toncto allow the use of a file as an argument. So if you have a busybox inside you can usebusybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.
– Kiwy
yesterday
2
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday
|
show 4 more comments
2
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access tobusybox echoorbusybox catcommands ?
– Kiwy
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.ENTRYPOINT ["/bin/sh", "-c", "mycommand"]is unnecessary, just doENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g.man 2 execve.
– gertvdijk
yesterday
1
Please read your question you need to use|to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module toncto allow the use of a file as an argument. So if you have a busybox inside you can usebusybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.
– Kiwy
yesterday
2
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday
2
2
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access to
busybox echo or busybox cat commands ?– Kiwy
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access to
busybox echo or busybox cat commands ?– Kiwy
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"] is unnecessary, just do ENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g. man 2 execve.– gertvdijk
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"] is unnecessary, just do ENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g. man 2 execve.– gertvdijk
yesterday
1
1
Please read your question you need to use
| to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module to nc to allow the use of a file as an argument. So if you have a busybox inside you can use busybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.– Kiwy
yesterday
Please read your question you need to use
| to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module to nc to allow the use of a file as an argument. So if you have a busybox inside you can use busybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.– Kiwy
yesterday
2
2
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday
|
show 4 more comments
3 Answers
3
active
oldest
votes
I don't know of any program that takes a parameter and sends it over a tcp connection.
However you have sort of answered your own question somewhat within your comments, specifically with the following line.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]
I appreciate that you seem to want the minimalist footprint of applications in your image, but I believe the best solution is to have a shell and netcat., then use your original command. Well at least to test whatever you are trying to do.
If at the end of the day, you want to drop back to only one executable, you'll have to write your own program to do it.
One thought, I see this example, shows setup of Python to run a script,
FROM python:2.7-slim AS build-env
ADD . /app
WORKDIR /app
FROM gcr.io/distroless/python2.7
COPY --from=build-env /app /app
WORKDIR /app
CMD ["hello.py", "/etc"]
which might be easier/quicker than developing a C program to do it all, but then effectively you are using Python as the SHELL. Lastly, if you think socat would do what you want, could you use socat to read from a file (which you include in your image), and that file contains your literal string.
edited yesterday
sourcejedi
25.5k445110
answered yesterday
X TianX Tian
7,78112237
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
add a comment |
I've written my own small application to implement what I need. Reads arguments and writes them to a socket. Too bad that it didn't exist yet, but only more complicated features are available in tools like nc and socat. Perhaps I might find time to write a patch to nc to also accept input from an argument.
Re comments - I find it a bit sad to read including a full shell and spawning subprocesses from it is the new norm. Pure overhead we don't need.
answered yesterday
gertvdijkgertvdijk
7,49252945
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it asherestring text nc -N host port. (that will not append a newline totext, unlikeecho text).
– mosvy
yesterday
add a comment |
I suppose you could use newlisp, such as
newlisp -e '(write-line (net-connect "localhost" 3456) "go for it")'
and vary parameters as desired.
I'm pretty sure you could use perl or other interpreters as well, though newlisp is quite small and it can be compiled into a static program as well.
The above example will make the program connect to localhost port 3456, and issue the line go for it on the socket, then it will exit. Goto the newlisp home site for more details.
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
add a comment |
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3 Answers
3
active
oldest
votes
3 Answers
3
active
oldest
votes
active
oldest
votes
active
oldest
votes
I don't know of any program that takes a parameter and sends it over a tcp connection.
However you have sort of answered your own question somewhat within your comments, specifically with the following line.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]
I appreciate that you seem to want the minimalist footprint of applications in your image, but I believe the best solution is to have a shell and netcat., then use your original command. Well at least to test whatever you are trying to do.
If at the end of the day, you want to drop back to only one executable, you'll have to write your own program to do it.
One thought, I see this example, shows setup of Python to run a script,
FROM python:2.7-slim AS build-env
ADD . /app
WORKDIR /app
FROM gcr.io/distroless/python2.7
COPY --from=build-env /app /app
WORKDIR /app
CMD ["hello.py", "/etc"]
which might be easier/quicker than developing a C program to do it all, but then effectively you are using Python as the SHELL. Lastly, if you think socat would do what you want, could you use socat to read from a file (which you include in your image), and that file contains your literal string.
edited yesterday
sourcejedi
25.5k445110
answered yesterday
X TianX Tian
7,78112237
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
add a comment |
I don't know of any program that takes a parameter and sends it over a tcp connection.
However you have sort of answered your own question somewhat within your comments, specifically with the following line.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]
I appreciate that you seem to want the minimalist footprint of applications in your image, but I believe the best solution is to have a shell and netcat., then use your original command. Well at least to test whatever you are trying to do.
If at the end of the day, you want to drop back to only one executable, you'll have to write your own program to do it.
One thought, I see this example, shows setup of Python to run a script,
FROM python:2.7-slim AS build-env
ADD . /app
WORKDIR /app
FROM gcr.io/distroless/python2.7
COPY --from=build-env /app /app
WORKDIR /app
CMD ["hello.py", "/etc"]
which might be easier/quicker than developing a C program to do it all, but then effectively you are using Python as the SHELL. Lastly, if you think socat would do what you want, could you use socat to read from a file (which you include in your image), and that file contains your literal string.
edited yesterday
sourcejedi
25.5k445110
answered yesterday
X TianX Tian
7,78112237
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
add a comment |
I don't know of any program that takes a parameter and sends it over a tcp connection.
However you have sort of answered your own question somewhat within your comments, specifically with the following line.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]
I appreciate that you seem to want the minimalist footprint of applications in your image, but I believe the best solution is to have a shell and netcat., then use your original command. Well at least to test whatever you are trying to do.
If at the end of the day, you want to drop back to only one executable, you'll have to write your own program to do it.
One thought, I see this example, shows setup of Python to run a script,
FROM python:2.7-slim AS build-env
ADD . /app
WORKDIR /app
FROM gcr.io/distroless/python2.7
COPY --from=build-env /app /app
WORKDIR /app
CMD ["hello.py", "/etc"]
which might be easier/quicker than developing a C program to do it all, but then effectively you are using Python as the SHELL. Lastly, if you think socat would do what you want, could you use socat to read from a file (which you include in your image), and that file contains your literal string.
edited yesterday
sourcejedi
25.5k445110
answered yesterday
X TianX Tian
7,78112237
I don't know of any program that takes a parameter and sends it over a tcp connection.
However you have sort of answered your own question somewhat within your comments, specifically with the following line.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]
I appreciate that you seem to want the minimalist footprint of applications in your image, but I believe the best solution is to have a shell and netcat., then use your original command. Well at least to test whatever you are trying to do.
If at the end of the day, you want to drop back to only one executable, you'll have to write your own program to do it.
One thought, I see this example, shows setup of Python to run a script,
FROM python:2.7-slim AS build-env
ADD . /app
WORKDIR /app
FROM gcr.io/distroless/python2.7
COPY --from=build-env /app /app
WORKDIR /app
CMD ["hello.py", "/etc"]
which might be easier/quicker than developing a C program to do it all, but then effectively you are using Python as the SHELL. Lastly, if you think socat would do what you want, could you use socat to read from a file (which you include in your image), and that file contains your literal string.
edited yesterday
sourcejedi
25.5k445110
answered yesterday
X TianX Tian
7,78112237
edited yesterday
sourcejedi
25.5k445110
edited yesterday
sourcejedi
25.5k445110
edited yesterday
sourcejedi
25.5k445110
25.5k445110
answered yesterday
X TianX Tian
7,78112237
answered yesterday
X TianX Tian
7,78112237
answered yesterday
X TianX Tian
7,78112237
7,78112237
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
add a comment |
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
This is not an answer to my question, sorry. I was asking if there was a program already that implements the 10 lines of C code to write arguments to a socket, instead stdin.
– gertvdijk
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
I started my answer saying I don't think there is such a program, and then went on to suggest alternative solutions. I also think having a couple of utilities (shell, php, busbox) still constitutes a distroless container, minimising the the available targets.
– X Tian
yesterday
add a comment |
I've written my own small application to implement what I need. Reads arguments and writes them to a socket. Too bad that it didn't exist yet, but only more complicated features are available in tools like nc and socat. Perhaps I might find time to write a patch to nc to also accept input from an argument.
Re comments - I find it a bit sad to read including a full shell and spawning subprocesses from it is the new norm. Pure overhead we don't need.
answered yesterday
gertvdijkgertvdijk
7,49252945
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it asherestring text nc -N host port. (that will not append a newline totext, unlikeecho text).
– mosvy
yesterday
add a comment |
I've written my own small application to implement what I need. Reads arguments and writes them to a socket. Too bad that it didn't exist yet, but only more complicated features are available in tools like nc and socat. Perhaps I might find time to write a patch to nc to also accept input from an argument.
Re comments - I find it a bit sad to read including a full shell and spawning subprocesses from it is the new norm. Pure overhead we don't need.
answered yesterday
gertvdijkgertvdijk
7,49252945
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it asherestring text nc -N host port. (that will not append a newline totext, unlikeecho text).
– mosvy
yesterday
add a comment |
I've written my own small application to implement what I need. Reads arguments and writes them to a socket. Too bad that it didn't exist yet, but only more complicated features are available in tools like nc and socat. Perhaps I might find time to write a patch to nc to also accept input from an argument.
Re comments - I find it a bit sad to read including a full shell and spawning subprocesses from it is the new norm. Pure overhead we don't need.
answered yesterday
gertvdijkgertvdijk
7,49252945
I've written my own small application to implement what I need. Reads arguments and writes them to a socket. Too bad that it didn't exist yet, but only more complicated features are available in tools like nc and socat. Perhaps I might find time to write a patch to nc to also accept input from an argument.
Re comments - I find it a bit sad to read including a full shell and spawning subprocesses from it is the new norm. Pure overhead we don't need.
answered yesterday
gertvdijkgertvdijk
7,49252945
edited yesterday
answered yesterday
gertvdijkgertvdijk
7,49252945
answered yesterday
gertvdijkgertvdijk
7,49252945
answered yesterday
gertvdijkgertvdijk
7,49252945
7,49252945
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it asherestring text nc -N host port. (that will not append a newline totext, unlikeecho text).
– mosvy
yesterday
add a comment |
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it asherestring text nc -N host port. (that will not append a newline totext, unlikeecho text).
– mosvy
yesterday
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it as
herestring text nc -N host port. (that will not append a newline to text, unlike echo text).– mosvy
yesterday
Instead of writing such a narrow utililty, you could've written a wrapper that "transforms" some command line arguments into a file and then exec's another program with its stdin redirected from it. Simple POC (linux-only) here. You can use it as
herestring text nc -N host port. (that will not append a newline to text, unlike echo text).– mosvy
yesterday
add a comment |
I suppose you could use newlisp, such as
newlisp -e '(write-line (net-connect "localhost" 3456) "go for it")'
and vary parameters as desired.
I'm pretty sure you could use perl or other interpreters as well, though newlisp is quite small and it can be compiled into a static program as well.
The above example will make the program connect to localhost port 3456, and issue the line go for it on the socket, then it will exit. Goto the newlisp home site for more details.
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
add a comment |
I suppose you could use newlisp, such as
newlisp -e '(write-line (net-connect "localhost" 3456) "go for it")'
and vary parameters as desired.
I'm pretty sure you could use perl or other interpreters as well, though newlisp is quite small and it can be compiled into a static program as well.
The above example will make the program connect to localhost port 3456, and issue the line go for it on the socket, then it will exit. Goto the newlisp home site for more details.
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
add a comment |
I suppose you could use newlisp, such as
newlisp -e '(write-line (net-connect "localhost" 3456) "go for it")'
and vary parameters as desired.
I'm pretty sure you could use perl or other interpreters as well, though newlisp is quite small and it can be compiled into a static program as well.
The above example will make the program connect to localhost port 3456, and issue the line go for it on the socket, then it will exit. Goto the newlisp home site for more details.
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
I suppose you could use newlisp, such as
newlisp -e '(write-line (net-connect "localhost" 3456) "go for it")'
and vary parameters as desired.
I'm pretty sure you could use perl or other interpreters as well, though newlisp is quite small and it can be compiled into a static program as well.
The above example will make the program connect to localhost port 3456, and issue the line go for it on the socket, then it will exit. Goto the newlisp home site for more details.
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
answered yesterday
Ralph RönnquistRalph Rönnquist
2,69759
2,69759
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
add a comment |
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
JRE ?? Not sure where you got that one from.
– Ralph Rönnquist
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
newlisp.org/index.cgi?Downloads shows a JRE dependency to me?
– gertvdijk
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
It's a bit of bad advertising, I think :) Of course one can run newlisp with a Java process as a front-end, if it's too hard to do terminal interaction. But that is newlisp plus a front-end. You don't want/need a front-end, esp. as you want to execute only the command line script.
– Ralph Rönnquist
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Oh, yeah I see it now. The JRE is for development. I see that the actual binary is quite lightweight, thanks. Still, some libreadline I see I don't have in the container, but yeah, close enough for an answer!
– gertvdijk
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
Yes. Normal build requires libreadline, libffi and libdl. Though it's quite easy to build a binary without needing any of them (and lose the related functionality of course). Ask at newlispfanclub.alh.net if you need.
– Ralph Rönnquist
yesterday
add a comment |
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2
If you haven't got a shell, what are you expecting to run your command ?
– X Tian
yesterday
you must have somekind of shell if you can run netcat inside your docker. Don't you have access to
busybox echoorbusybox catcommands ?– Kiwy
yesterday
@XTian Uhm, you can run commands without a shell! In fact, that's what best practice in containerized environments. E.g.
ENTRYPOINT ["/bin/sh", "-c", "mycommand"]is unnecessary, just doENTRYPOINT ["mycommand"]. Also more generally, when processes spawn other processes, you don't want to invoke a full shell, see e.g.man 2 execve.– gertvdijk
yesterday
1
Please read your question you need to use
|to execute your command, pipe is part of the shell so you either need a shell/bash/zsh to execute your command either you develop a module toncto allow the use of a file as an argument. So if you have a busybox inside you can usebusybox sh. Distroless is oriented toward application execution so you could either use a python application to do what you want stackoverflow.com/q/1908878/1195001 or use an other docker image as it seems this one doesn't fulfil your goal.– Kiwy
yesterday
2
So you have some restriction on the collection of programs available in your docker environment, and you want someone to guess which of those programs can do the work of reading from a socket and writing to it, and also spawning some other program. It would then help if you then tell which programs you do have rather then telling some you don't have.
– Ralph Rönnquist
yesterday