I am trying to get the time of the process start.
Usually I use the brackets on the first letter of the process that I am running.
It takes away the self reporting "grep" in the ps output.
#!/bin/bash
set -x
restarTXG="sendevent -E FORCE_STARTJOB -J CASPERRT_CD_TXG_DR_STR_PS"
bounceTXG="sendevent -E FORCE_STARTJOB -J CASPERRT_CD_TXG_DR_STP_PS; sleep 10 ; sendevent -E FORCE_STARTJOB -J CASPERRT_CD_TXG_DR_STR_PS"
timeofTXG=$(ps -ef | grep [t]xg | awk '{print $5}' )
if [ -n "$timeofTXG" ] ; then
printf "%s\n" "The TXG_DR is ON as of $timeofTXG"
else
printf "%s\n" "'The TXG_DR is OFF"
fi
18:40 is the time I run the check script. 17:44 is the time the process started.
++ ps -ef
++ grep '[t]xg'
++ awk '{print $5}'
+ timeofTXG='17:44
18:40
18:40'
+ '[' -n '17:44
18:40
18:40' ']'
+ printf '%s\n' 'The TXG_DR is ON as of 17:44
18:40
18:40'
The TXG_DR is ON as of 17:44
18:40
18:40
I don't really know how the square brackets work. When I run the ps from the command line, the [] brackets do work -- ps -ef | grep [t]xg | awk '{print $5}'
however in the context of the bash script, they are not working, they are giving me the time of the self reporting grep.
How do the brackets work? Why do they work on the command line and not in the script? How do I get rid of the self revealing grep in bash script ?
If you are running awk already you don't need grep, do something like this (which I guess is your intention):
ps -ef | awk '$8 ~ /txg/ {print $5}'
Related
I need help completing this. Trying to take user sessions sitting idle for greater than 15 minutes which aren't being kicked off by sshd_config and kill them. this is what I have to pull the sessions, how do I filter for greater than 15 minutes.
#!/bin/bash
IFS=$'\n'
for output in $(w | tr -s " " | cut -d" " -f1,5 | tail -n+3 | awk '{print $2}')
do
echo "$output \> 15:00"
done
If you are using Awk anyway, a shell loop is a clumsy antipattern. Awk already knows how to loop over lines; use it.
A serious complication is that the output from w is system-dependent and typically reformatted for human legibility.
tripleee$ w | head -n 4
8:16 up 37 days, 19:02, 17 users, load averages: 3.49 3.21 3.11
USER TTY FROM LOGIN# IDLE WHAT
tripleee console - 27Aug18 38days -
tripleee s003 - 27Aug18 38 ssh -t there screen -D -r
If yours looks similar, probably filter out anything where the IDLE field contains non-numeric information
w -h | awk '$5 ~ /[^0-9]/ || $5 > 15'
This prints the entire w output line. You might want to extract just the TTY field ({print $2} on my system) and figure out from there which session to kill.
A more fruitful approach on Linux-like systems is probably to examine the /proc filesystem.
You can try something like this …
for i in $(w --no-header | awk '{print $4}')
do
echo $i | grep days > /dev/null 2>&1
if [ $? == 0 ]
then
echo "greater that 15 mins"
fi
echo $i | grep min> /dev/null 2>&1
if [ $? == 0 ]
then
mins=$(echo $i | sed -e's/mins//g')
if [ $min -gt 15 ]
then
echo "Greater than 15 mins"
fi
fi
done
The tricky part is going to be figuring out what pid to kill.
Context
Got a daft script that checks a process is running on a group of hosts, like a watchdog, as I say it's a daft script so bear in mind it isn't 'perfect' by scripting standards
Problem
I've ran bash -x and can see that the script finishes its first check without actually redirecting the output of the command to the file which is very frustrating, it means each host is actually being evaluated to the last hosts output
Code
#!/bin/bash
FILE='OUTPUT'
for host in $(cat /etc/hosts | grep webserver.[2][1-2][0-2][0-9] | awk {' print $2 ' })
do ssh -n -f $host -i <sshkey> 'ps ax | grep myprocess | wc -l' > $FILE 2> /dev/null
cat $FILE
if grep '1' $FILE ; then
echo "Process is NOT running on $host"
cat $FILE
else
cat $FILE
echo "ALL OK on $host"
fi
cat $FILE
done
Script traceback
++ cat /etc/hosts
++ awk '{ print $2 }'
++ grep 'webserver.[2][1-2][0-2][0-9]'
+ for host in '$(cat /etc/hosts | grep webserver.[2][1-2][0-2][0-9] | awk {'\'' print $2 '\''})'
+ ssh -n -f webserver.2100 -i <omitted> 'ps ax | grep myprocess | wc -l'
+ cat OUTPUT
+ grep 1 OUTPUT
+ cat OUTPUT
+ echo 'ALL OK on webserver.2100'
ALL OK on webserver.2100
+ cat OUTPUT
+ printf 'webserver.2100 checked \n'
webserver.2100 checked
+ for host in '$(cat /etc/hosts | grep webserver.[2][1-2][0-2][0-9] | awk {'\'' print $2 '\''})'
+ ssh -n -f webserver.2101 -i <omitted> 'ps ax | grep myprocess | wc -l'
+ cat OUTPUT
2
+ grep 1 OUTPUT
+ cat OUTPUT
2
+ echo 'ALL OK on webserver.2101'
ALL OK on webserver.2101
+ cat OUTPUT
2
+ printf 'webserver.2101 checked \n'
webserver.2101 checked
Issue
As you can see, it's registering nothing for the first host, then after it is done, it's piping the data into the file, then the second host is being evaluated for the previous hosts data...
I suspect its to do with redirection, but in my eyes this should work, it doesn't so it's frustrating.
I think you're assuming that ps ax | grep myprocess will always return at least one line (the grep process). I'm not sure that's true. I'd rewrite that like this:
awk '/webserver.[2][1-2][0-2][0-9]/ {print $2}' /etc/hosts | while IFS= read -r host; do
output=$( ssh -n -f "$host" -i "$sshkey" 'ps ax | grep "[m]yprocess"' )
if [[ -z "$output" ]]; then
echo "Process is NOT running on $host"
else
echo "ALL OK on $host"
fi
done
This trick ps ax | grep "[m]yprocess" effectively removes the grep process from the ps output:
the string "myprocess" matches the regular expression "[m]yprocess" (that's the running "myprocess" process), but
the string "[m]yprocess" does not match the regular expression "[m]yprocess" (that's the running "grep" process)
Code sample :
declare -i a=1
echo "The number of NMON instances running in Performance VM"
ps -ef | grep nmon | awk '{ print $2 }' | wc -l
echo "---------------------------------------------"
num2= ps -ef | grep nmon | awk '{ print $2 }' | wc -l
#num1=${num2%%.*}
#num2 = $(ps -ef | grep nmon | awk '{ print $2 }' | wc -l)
echo "---------------------------------------------"
echo "${num2}"
while [ "$a" -lt "$num2" ]
do
kill -USR2 $(ps -ef | grep nmon | awk '{ print $2 }' | head -1)
a=`expr $a + 1`
done
In the Output i am getting the following error
[: : integer expression expected
in the debug it shows
++ '[' 1 -lt '' ']'
that num2 is empty but when i echo the num2 value i am getting the value correctly.
Output:
The number of NMON instances running in Performance VM
1
1
thanks in advance
The 1 you see in the output is not from echo "${num2}". Like the diagnostics already tell you, this variable is empty.
The general syntax of shell scripts is
[ variable=value ...] command parameters ...
which will assign value to variable for the duration of command, then restore its original value. So the pipeline you are running temporarily sets num2 to the empty string (which apparently it already contained anyway), then runs the pipeline without storing the output anywhere (such as, I imagine you expected, in num2).
Here is a fixed version of your script, with the additional change that the Awk scripts handle stuff you used grep and head and wc for. Because the functionality of these commands is easily replaced within Awk, using external utilities is doubtful (especially so for grep which really is useless when you just run it as a preprocessor for a simple Awk script).
countnmon () {
ps -ef | awk '/[n]mon/ { ++n } END { print n }'
}
declare -i a=1
echo "The number of NMON instances running in Performance VM"
countnmon
echo "---------------------------------------------"
num2=$(countnmon)
#num1=${num2%%.*}
#num2 = $(countnmon)
echo "---------------------------------------------"
echo "${num2}"
while [ "$a" -lt "$num2" ]
do
kill -USR2 $(ps -ef | awk '/[n]mon/ { print $2; exit }')
a=`expr $a + 1`
done
The repeated code could be refactored even further to avoid all code duplication but that will somewhat hamper the readability of this simple script so I have not done that.
Whitespaces matter in bash.
The syntax for command execution is:
command arg1 arg2 ...
So,
var = value # command: var, arg1: =, arg2: value
There's are two exceptions to this rule
exporting variables to an executed command (the variables vanish after the command finishes):
var1=value1 var2=value2 .. command arg1 arg2 ...
assigning a variable (you want this one):
var=value
This follows on from Faulty tail syntax or grep command? but I'm reading a live log entries for given conditions and when they're met continuing the execution of the rest of the script. I'm using this:
tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold"
FPC=$(echo $line | awk 'END { print substr($8,1,1) }')
PIC=$(echo $line | awk 'END { print substr($11,1,1) }')
echo FPC $FPC
echo PIC $PIC
echo "Running information gathering"...and rest of script.
Which works perfectly for the conditions detection and further execution, but I don't have the log entry to test for the FPC and PIC variables. I've tried wrapping the tail statement thus:
line=$(tail -Fn0 /var/log/messages | grep -q "CPU utilization" | grep -q "exceeded threshold")
but grep -q exits silently and the $line variable is blank. I've tried:
line=$(tail -Fn0 /var/log/messages | grep -m1 "CPU utilization" | grep -m1 "exceeded threshold")
which doesn't work until I attempt to CONTROL-C out of the script. Then it works fine and continues perfectly. Can someone help please?
I need the variables FPC and PIC later in the script.
Assuming that you don't need these variables later on, you could do something like this:
tail -Fn0 /var/log/messages | \
awk '/CPU utilization/ && /exceeded threshold/ {
print "FPC", substr($8,1,1); print "PIC", substr($11,1,1); exit }'
When the line matches both patterns, print the two parts of it that you are interested in and exit.
If you do need the variables, you could do something like this instead:
line=$(tail -Fn0 /var/log/messages | awk '/CPU utilization/&&/exceeded threshold/{print;exit}')
FPC=$(echo "$line" | awk '{ print substr($8,1,1) }')
PIC=$(echo "$line" | awk '{ print substr($11,1,1) }')
I am trying to write a script to find a reverse SSH PID and kill it if present. I am stuck on "awk" as it gives error. below is the script:
a=('ps -aef | grep "ssh -fN" | grep -v grep | awk '{ print $2 }'')
if [ -n "$a" ]
then
echo "String \"$a\" is not null."
kill -9 "$a"
fi
I commented out if, then, kill and fi lines to debug the script. I get following error:
String "ps -aef | grep "ssh -fN" | grep -v grep | awk {" is not null.
I believe parenthesis for awk is creating the problem and I am unable to get a workaround for this. On Command line, this works perfectly and returns the correct PID.
ps -aef | grep "ssh -fN" | grep -v grep | (awk '{ print $2 }'
Once the PID is passed on to variable "a", I need to issue kill command. OS is Centos 6.4
P.S: I am not fluent on scripting but trying to achieve an objective. Help will be highly appreciated!
There are multiple problems with your script.
You need command substitution to store the output of ps pipeline into an array.
You need to check for the number of elements in the array.
Refer to the array instead of the variable.
The following might work for you:
pids=( $(ps -ef | grep '[s]sh -fN' | awk '{print $2}') )
if [ "${#pids[#]}" -gt 0 ]; then
kill -9 "${pids[#]}";
fi
First, if you have grep and then awk, you can get rid of the greps:
ps -aef | grep "ssh -fN" | grep -v grep | awk '{ print $2 }'
ps -aef |awk ' { if ( ($0 ~ /ssh -FN/) && (! $0 ~ /grep/) ) { print $2 } }'
However, instead of using ps, use pgrep.
pgrep -f "ssh -[fN][fN]" # Will match against either 'ssh -fN' or 'ssh -Nf'
There is even a pkill that will do the entire command for you:
pkill -f "ssh -[fN][fN]"
That will find all of the processes that match that particular string and kill them (if they exist).