Use remote server env variable in ksh via an SSH command - unix

I can't find any answer to this "easy looking" problem.
I would like to execute an ssh command using a ksh shell or script which use an env variable of the SERVER.
Example:
ssh user#server "ls $DIR"
Where $DIR is an env variable define on the server (in this case: a directory path) and not the $DIR define on my client env.
In worst case scenario I can use something like env | grep DIR | cut -d "=" -f 2
to get the var but it looks weird.
Thanks for any help.

ssh user#server "ls $DIR"
Double-quoted strings undergo variable interpolation. So "$DIR" is being replaced on the local system, then the shell invokes the ssh command with the resulting string.
To pass the literal command through to the remote system, use single quotes:
ssh user#server 'ls $DIR'

The SSH command execution shell is a non-interactive shell, whereas your normal shell is either a login shell or an interactive shell.
In fact not all environment varialbles are available in non-interactive shell, you need to check ksh manual to figure out the configuration files that ksh reads when running in non-interactive mode, in case of bash those are roughly following
/etc/profile
~/.bash_profile
~/.bash_login
~/.profile
Just find out the corresponding ones for ksh and move/copy your DIR environment variable definition to there on sever side.

Related

Unable to export env variable from script

I'm currently struggling with running a .sh script I'm trying to trigger from Jenkins.
Within the Jenkins "execute shell" section, I'm connecting to a remote server (The Jenkins agent does not have right OS to build what I need.), using:
cp -r . /to/shared/drive/to/have/access/on/remote
ssh -t -t username#servername << EOF
cd /to/shared/drive/to/have/access/on/remote
source build.sh dev
exit
EOF
Inside build.sh, I'm exporting R_LIBS to build a package for different R versions.
...
for path in "${!rVersionPaths[#]}"; do
export R_LIBS="${path}"
Rscript -e 'install.packages(c("someDependency", "someOtherDependency"), repos="http://cran.r-project.org");'
...
Setting R_LIBS should functions here like setting lib within install.packages(...). For some reason the R_LIBS export doesn't get picked up. Also setting other env variables like http_proxy are ignored. This causes any requests outside the network to fail.
Is there any particular way of achieving this?
Maybe pass those variables with env, like
env R_LIBS="${path}" Rscript -e 'install.packages(c("someDependency", .....
Well i'm not able to comment on the question, so posting it as answer.
I had similar problem when calling remote shell script from Jenkins, the problem was somehow bash_profile variables were not loaded when called the script from Jenkins but locally it worked. Loading the bash profile in ssh connection solved it for me.
Add source to bash_profile in build.sh
. ~/.bash_profile OR source ~/.bash_profile
Or
Reload bash_profile in ssh connection
`ssh -t -t username#servername << EOF
. ~/.bash_profile
your commands here
exit
EOF
You can set that variable in the same command line like this:
R_LIBS="${path}" Rscript -e \
'install.packages(c("someDependency", "someOtherDependency"), repos="http://cran.r-project.org");'
It's possible to append more variables in this way. Note that this will set those environment variables only for the command being called after them (and its children processes as well).
You said that "R_LIBS export doesn't get picked up". Question Is the value UNSET? Or is it set to some other value & you are trying to override it?
It is possible that SSH may be invoking "/bin/sh -c". Based on the second answer to: Why does 'cd' command not work via SSH?, you can simplify the SSH command and explicitly invoke the build.sh script in Bash:
cp -r . /to/shared/drive/to/have/access/on/remote
ssh -t -t username#servername "cd /to/shared/drive/to/have/access/on/remote && bash -f build.sh dev"
This makes the SSH invocation more similar to invoking the command within a remote interactive shell. (You can avoid sourcing scripts and exporting variables.)
You don't need to export R_LIBSor env R_LIBS when it is possible to prefix any command with local environment variable overrides (agrees with Luis' answer):
...
for path in "${!rVersionPaths[#]}"; do
R_LIBS="${path}" Rscript -e 'install.packages(c("someDependency", "someOtherDependency"), repos="http://cran.r-project.org");'
...
The Rscript may be doing a lot with env vars. You can verify that you are setting the R_LIBS env var by replacing Rscript with the env command and observe the output:
...
for path in "${!rVersionPaths[#]}"; do
R_LIBS="${path}" env
...
According to this manual "Initialization at Start of an R Session", Rscript looks in several places to load "site and user files":
$R_PROFILE
$R_HOME/etc/Renviron
$R_HOME/etc/Renviron.site
$R_ENVIRON_USER
$R_PROFILE_USER
./.Rprofile
$HOME/.Rprofile
./.RData
The "Examples" section of that manual shows this:
## Not run:
## Example ~/.Renviron on Unix
R_LIBS=~/R/library
PAGER=/usr/local/bin/less
If you add the --vanilla command-line option to ignore all of these files, then you may get different results and know something in the site/init/environ files is affecting your R_LIBS! I cannot run this system myself. Hopefully we have given you some areas to investigate.
You probably don't want to source build.sh, just invoke it directly (i.e. remove the source command).
By source-ing the file your script is executed in the SSH shell (likely sh) rather than by bash, which it sounds like is what you intended.

what is the first step of ssh copy execute in terminal?

I am using this command to copy file from remote server to local machine:
scp -r app:/home/dolphin/model* .
In bash it works fine.In zsh it throw this error:zsh: no matches found: app:/home/dolphin/model*.I am searching from Google and understand the bash and zsh have different rule of glob.Here is my question:
what is the execute step detail of this command?
anyone could tell me the shell how to execute the command,the first step is echo the path of this command?
I could use -v(verbose) to see the scp execute process.
I am unfamiliar with Zsh, but as far as I can say, Bash will pass the original string to the program as an argument if nothing is globbed, while it appears that Zsh complains in this case.
To ensure the "unglobbed" string is passed as an argument to scp(1), you can escape the asterisk:
scp -r app:/home/dolphin/model\* .
^^

How to modify PATH for non-interactive SSH call in RHEL 5?

I am trying to modify the PATH variable of my SSH server such at a non-interactive shell command ssh myserver.com 'echo $PATH' returns the desired path. I tried modifying ~/.bashrc and ~/.profile files but they only modify PATH for when I log in to the server interactively, i.e. ssh myserver.com.
Can I change this behavior in RHEL5?
~/.bash_profile is where you want to place these variables. I don't believe that bash uses ~/.profile ( I believe it is used by csh and tcsh )

How do you use an identity file with rsync?

How do you use an identity file with rsync?
This is the syntax I think I should be using with rsync to use an identity file to connect:
rsync -avz -e 'ssh -p1234 -i ~/.ssh/1234-identity' \
"/local/dir/" remoteUser#22.33.44.55:"/remote/dir/"
But it's giving me an error:
Warning: Identity file ~/.ssh/1234-identity not accessible: No such file or directory.
The file is fine, permissions are set correctly, it works when doing ssh - just not with rsync - at least in my syntax. What am I doing wrong? Is it trying to look for the identity file on the remote machine? If so, how do I specify that I want to use an identity file on my local machine?
Use either $HOME
rsync -avz -e "ssh -p1234 -i \"$HOME/.ssh/1234-identity\"" dir remoteUser#server:
or full path to the key:
rsync -avz -e "ssh -p1234 -i /home/username/.ssh/1234-identity" dir user#server:
Tested with rsync 3.0.9 on Ubuntu
You may want to use ssh-agent and ssh-add to load the key into memory. ssh will try identities from ssh-agent automatically if it can find them. Commands would be
eval $(ssh-agent) # Create agent and environment variables
ssh-add ~/.ssh/1234-identity
ssh-agent is a user daemon which holds unencrypted ssh keys in memory. ssh finds it based on environment variables which ssh-agent outputs when run. Using eval to evaluate this output creates the environment variables. ssh-add is the command which manages the keys memory. The agent can be locked using ssh-add. A default lifetime for a key can be specified when ssh-agent is started, and or specified for a key when it is added.
You might also want to setup a ~/.ssh/config file to supply the port and key definition. (See `man ssh_config for more options.)
host 22.33.44.55
IdentityFile ~/.ssh/1234-identity
Port 1234
Single quoting the ssh command will prevent shell expansion which is needed for ~ or $HOME. You could use the full or relative path to the key in single quotes.
You have to specify the absolute path to your identity key file. This probably some sort of quirck in rsync. (it can't be perfect after all)
I ran into this issue just a few days ago :-)
This works for me
rsync -avz --rsh="ssh -p1234 -i ~/.ssh/1234-identity" \
"/local/dir/" remoteUser#22.33.44.55:"/remote/dir/"
use key file with rsync:
rsync -rave "ssh -i /home/test/pkey_new.pem" /var/www/test/ ubuntu#231.210.24.48:/var/www/test
Are you executing the command in bash or sh? This might make a difference. Try replacing ~ with $HOME. Try double-quoting the string for the -e option.

Whats the difference between running a shell script as ./script.sh and sh script.sh

I have a script that looks like this
#!/bin/bash
function something() {
echo "hello world!!"
}
something | tee logfile
I have set the execute permission on this file and when I try running the file like this
$./script.sh
it runs perfectly fine, but when I run it on the command line like this
$sh script.sh
It throws up an error. Why does this happen and what are the ways in which I can fix this.
Running it as ./script.sh will make the kernel read the first line (the shebang), and then invoke bash to interpret the script. Running it as sh script.sh uses whatever shell your system defaults sh to (on Ubuntu this is Dash, which is sh-compatible, but doesn't support some of the extra features of Bash).
You can fix it by invoking it as bash script.sh, or if it's your machine you can change /bin/sh to be bash and not whatever it is currently (usually just by symlinking it - rm /bin/sh && ln -s /bin/bash /bin/sh). Or you can just use ./script.sh instead if that's already working ;)
If your shell is indeed dash and you want to modify the script to be compatible, https://wiki.ubuntu.com/DashAsBinSh has a helpful guide to the differences. In your sample it looks like you'd just have to remove the function keyword.
if your script is at your present working directory and you issue ./script.sh, the kernel will read the shebang (first line) and execute the shell interpreter that is defined. you can also call your script.sh by specifying the path of the interpreter eg
/bin/bash myscript.sh
/bin/sh myscript.sh
/bin/ksh myscript.sh etc
By the way, you can also put your shebang like this (if you don't want to specify full path)
#!/usr/bin/env sh
sh script.sh forces the script to be executed within the sh - shell.
while simply starting it from command line uses the shell-environemnt you're in.
Please post the error message for further answers.
Random though on what the error may be:
path specified in first line /bin/bash is wrong -- maybe bash is not installed?

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