What is the use of bash -c command, while surfing on the internet I came across the command
ssh -t "${SSH_USER}#${SERVER_IP}" bash -c
First part here is doing ssh obviously to a server but what exactly bash -c is responsible for?
bash -c option with ssh is one such method to execute multi line commands on the ssh server with variable expansion.
Say you have
VAR1="Variable 1"
ssh app#HOSTNAME '
ls
pwd
if true; then
echo "True"
echo $VAR1 # <-- it won't work
else
echo "False"
fi
'
But with bash -c
VAR1="Variable 1"
ssh -t "${SSH_USER}#${SERVER_IP}" bash -c "'
ls
pwd
if true; then
echo $VAR1 <-- This works
else
echo "False"
fi
'"
Related
I have the following bash script:
#!/bin/bash
set command "pgrep -x 'gedit' "
ssh -t test#192.168.94.139 $command
Now, I want to include this as well in the other device:
if pgrep -x "gedit" > /dev/null
then
echo "Running"
else
echo "Not Running"
fi
How can I make the IF Statement run on the other device? I wasn't able to include it in the ssh.
I tried this:
set command "pgrep -x 'gedit' "
ssh -t test#192.168.94.139 '
if pgrep -x "gedit" > /dev/null
then
echo "Running"
else
echo "Not Running"
fi'
But it didn't work! maybe because there is no command at the beginning?
Thanks.
Invoke bash with heredoc:
ssh -t test#192.168.94.139 bash <<EOF
if pgrep -x "gedit" > /dev/null
then
echo "Running"
else
echo "Not Running"
fi
EOF
I have a csv file called addresses.csv which looks like this,
node-1,xx.xxx.xx.xx,us-central-a
....
node-9,xxx.xx.xxx.xx,us-east1-a
I have a script below called 0run.sh,
#!/bin/bash
username='user'
persist="bash /home/${username}/Documents/scripts/disk/persistentDisk.sh"
first="bash /home/${username}/Documents/scripts/disk/firstAttach.sh"
while IFS=, read -r int ip <&3; do
if [ "$int" == "node-1" ]; then
--->ssh -i ~/.ssh/key -o StrictHostKeyChecking=no -l ${username} ${ip} "${persist}; ${first}"<---
else
ssh -i ~/.ssh/key -o StrictHostKeyChecking=no -l ${username} ${ip} "${first}"
fi
done 3<addresses.csv
The error occurs in the part of the code where I drew the arrows.
When it runs on node-1, instead of running ..persistentDisk.sh followed by ..firstAttach.sh, it only runs ..persistentDisk.sh and gives me the following error before it runs ..persistentDisk.
bash: /home/user/Documents/scripts/disk/firstAttach.sh: No such file or directory
The rest of the script runs completely fine. The only error occurs at this one part where it misses the 2nd script.
When I run the command like this it runs fine.
ssh -i ~/.ssh/key -o StrictHostKeyChecking=no -l ${username} ${ext} "${first}"
When I run it like this, it runs fine as well.
ssh -i ~/.ssh/key -o StrictHostKeyChecking=no -l user xxx.xx.xxx.xx "bash /home/${username}/Documents/scripts/disk/persistentDisk.sh; bash /home/${username}/Documents/scripts/disk/firstAttach.sh"
When I run the command like with a \ before the ; to escape it like this,
ssh -i ~/.ssh/key -o StrictHostKeyChecking=no -l ${username} ${ext} "${persist}\; ${first}"
I get the following error, and neither scripts run within the node-1 part of the code, but the rest of the code's else loops run fine.
bash: /home/user/Documents/scripts/disk/persistentDisk.sh;: No such file or directory
Why can't I stack the 2 commands within the if statement in the ssh using variables?
If I clearly understand: your real problem consist to leave STDIN free for interaction in target host!
About read and redirection
Try using:
#!/bin/bash
username='user'
persist="bash /home/${username}/Documents/scripts/disk/persistentDisk.sh"
first="bash /home/${username}/Documents/scripts/disk/firstAttach.sh"
while IFS=, read -r -u $list int ip foo; do
if [ "$int" == "node-1" ]; then
echo CMD... $ip, $persist
else
[ "$ip" ] && echo CMD... $ip, $first
fi
done {list}<addresses.csv
Tested, this èroduce:
CMD... xx.xxx.xx.xx, bash /home/user/Documents/scripts/disk/persistentDisk.sh
CMD... xxx.xx.xxx.xx, bash /home/user/Documents/scripts/disk/firstAttach.sh
-u flag to read, tell to use file descriptor ${list} instead of STDIN
foo is some useless variable used to prevent rest of line to be stored in $ip (xx.xxx.xx.xx,us-central-a in this case)
{list}</path/to/filename create a new variable by finding any free file descriptor.
About ssh (and redirection)
You could use:
#!/bin/bash
username='user'
persist="/home/${username}/Documents/scripts/disk/persistentDisk.sh"
first="/home/${username}/Documents/scripts/disk/firstAttach.sh"
while IFS=, read -r -u $list int ip foo; do
[ "$int" = "node-1" ] && cmd=persist || cmd=first
[ "$ip" ] && ssh -i ~/.ssh/key -t -o StrictHostKeyChecking=no \
-l ${username} ${ext} /bin/bash "${!cmd}"
done {list}<addresses.csv
By using this syntax, you will keep STDIN free for script running on target host.
I've placed a bash file inside .zshrc and tried all different ways to run it every time I open a new terminal window or source .zshrc but no luck.
FYI: it was working fine on .bashrc
here is .zshrc script:
#Check if ampps is running
bash ~/ampps_runner.sh & disown
Different approach:
#Check if ampps is running
sh ~/ampps_runner.sh & disown
Another approach:
#Check if ampps is running
% ~/ampps_runner.sh & disown
All the above approaches didn't work (meaning it supposes to run an app named ampps but it doesn't in zsh.
Note: It was working fine before switching to zsh from bash. so it does not have permission or syntax problems.
Update: content of ampps_runner.sh
#! /usr/bin/env
echo "########################"
echo "Checking for ampps server to be running:"
check=$(pgrep -f "/usr/local/ampps" )
#[ -z "$check" ] && echo "Empty: Yes" || echo "Empty: No"
if [ -z "$check" ]; then
echo "It's not running!"
cd /usr/local/ampps
echo password | sudo -S ./Ampps
else
echo "It's running ..."
fi
(1) I believe ~/.ampps_runner.sh is a bash script, so, its first line should be
#!/bin/bash
or
#!/usr/bin/bash
not
#! /usr/bin/env
(2) Then, the call in zsh script (~/.zshrc) should be:
~/ampps_runner.sh
(3) Note: ~/.ampps_runner.sh should be executable. Change it to executable:
$ chmod +x ~/ampps_runner.sh
The easiest way to run bash temporarily from a zsh terminal is to
exec bash
or just
bash
Then you can run commands you previously could only run in bash. An example
help exec
To exit
exit
Now you are back in your original shell
If you want to know your default shell
echo $SHELL
or
set | grep SHELL=
If you want to reliably know your current shell
ps -p $$
Or if you want just the shell name you might use
ps -p $$ | awk "NR==2" | awk '{ print $4 }' | tr -d '-'
And you might just put that last one in a function for later, just know that it is only available if it was sourced in a current shell.
whichShell(){
local defaultShell=$(echo $SHELL | tr -d '/bin/')
echo "Default: $defaultShell"
local currentShell=$(ps -p $$ | awk "NR==2" | awk '{ print $4 }' | tr -d '-')
echo "Current: $currentShell"
}
Call the method to see your results
whichShell
I'm sending a command through ssh:
ssh server.org 'bash -s' << EOF
ls -al
whoami
uptime
EOF
How to log it in the system (remote server)? I'd like to log those commands in some file (.bash_history or /tmp/log).
I've tried to add the line below to sshd_config:
ForceCommand if [[ -z $SSH_ORIGINAL_COMMAND ]]; then bash; else echo "$SSH_ORIGINAL_COMMAND" >> .bash_history; bash -c "$SSH_ORIGINAL_COMMAND"; fi
But it logs "bash -s" only.
I'll appreciate any help.
When bash shell exits, bash reads and executes commands from the ~/.bash_logout file. Probably you can run the history command at the end in the .bash_logout(of the server) and save it to some location.
If it suffices to work with the given command, we can put the necessary additions to enable and log command history at the beginning and end, e. g.
ssh server.org bash <<EOF
set -o history
ls -al
whoami
uptime
history|sed 's/ *[0-9]* *//' >>~/.bash_history
EOF
Or we could put them into the awfully long ForceCommand line:
… if [[ "$SSH_ORIGINAL_COMMAND" == bash* ]]; then echo "set -o history"; cat; echo "history|sed 's/ *[0-9]* *//' >>~/.bash_history"; else cat; fi | bash -c "$SSH_ORIGINAL_COMMAND"; fi
This script required an ip and the script or file that we have to run on the remote server i gave a file in which i have wrote commands like
touch /root/test
ls /root/test
this make the file but do not show and it is displaying an error
tcgetattr: Inappropriate ioctl for device
connection closed
How can I resolve this is there any suggestion ??
#!/bin/bash
# The private key used to identify this machine
IDENTITY_KEY=/home/admnew.pem
syntax()
{
echo "Syntax: Ec2.sh server_ip scriptFile]"
echo "For example: ./Ec2.sh server_ip scriptFile"
exit 1
}
if [ $# -ne 2 ]
then
echo not enough arguments
syntax
fi
echo "Running script $2 on $1"
ssh -t -t -i $IDENTITY_KEY ec2-user#$1 sudo -i 'bash -s' < $2
exit
exit
echo "Done"
Try:
ssh -t -t -i $IDENTITY_KEY ec2-user#$1 sudo -i 'bash -s' <<EOF
(
$(cat "$2")
)
EOF
e.g. wrap the script into (), e.g the:
touch /root/test
ls /root/test
should be
(
touch /root/test
ls /root/test
)