script in bash for sending mail if CPU exceeds - linux

I have this script:
#!/bin/bash
# rsync using variables
CPU=$(sar 1 5 | grep "Average" | sed 's/^.* //')
if [ $CPU -lt 100 ]
then
cat mail_content.html | /usr/lib/sendmail -t
else
echo "Normal"
fi
when I am executing it I am getting the following error message:
./monitor_cpu.sh: line 6: [: 99.25: integer expression expected
Normal
I want it to be able to identify that the number x.x (99.25) will be recognized which is not happening right now.

Alternatively, if CPU is not an integer, you can use bc to compare it.
echo "$CPU < 100" | bc
Then if the result is 1, the value of CPU will be less than 100. So you can do:
[ $(echo "$CPU < 100" | bc) -eq 1 ] && echo yes
Or, you can convert it to integer with printf:
printf '%.0f' "$CPU"

The problem is that -eq does not compare floats, as explained here. Thus, you need to use bc.
#!/bin/bash
# rsync using variables
CPU=$(LANG=C sar 1 5 | grep "Average" | sed 's/^.* //')
if (( $(echo "$CPU < 100" |bc -l) ))
then
cat mail_content.html | /usr/lib/sendmail -t
else
echo "Normal"
fi

Related

Shell script having problems

#!/bin/bash
while [ true ]
do
echo "$(top -b -o +%MEM -n 1 | head -n +8 | tail -n 1 | awk '{ print $12";"$10 }');$(date +'%H:%M:%S')" >> RAM.csv
if [ -z "$1" ]; then
sleep 1m
else
sleep "$1"
fi
done
ERROR OUTPUT : date: extra operand '%H:%M:%S'
what is wrong with this?
Below you find a mildly improved version of your script:
#!/usr/bin/env bash
# All output is appended to RAM.csv
exec >> RAM.csv
# Do an infinite loop
while :; do
# Get command with most used memory, print it in CSV format, append time
date "+$(ps -eo ucmd -o '%mem' --sort=-%mem h | awk -v OFS=";" '($1=$1);{exit}');%T"
# sleep $1 seconds, if not defined 1m
sleep "${1:-1m}"
done

Comparing floating-point numbers in bash [duplicate]

This question already has answers here:
Floating point comparison with variable in bash [duplicate]
(2 answers)
Closed 6 years ago.
In my custom bash script for server monitoring , which actually made to force my CentOS server take some actions and alert me if resources are overloaded more time than expected, I get the following error
line 17: [: 5.74: integer expression expected *
Now by definition all iostat results are float numbers and I already have used awk in my iostat command (WAIT) so how I can make my bash script to expect one instead of integer ?
** Value 5.74 represents current iostat result
#!/bin/bash
if [[ "`pidof -x $(basename $0) -o %PPID`" ]]; then
# echo "Script is already running with PID `pidof -x $(basename $0) -o %PPID`"
exit
fi
UPTIME=`cat /proc/uptime | awk '{print $1}' | cut -d'.' -f1`
WAIT=`iostat -c | head -4 |tail -1 | awk '{print $4}' |cut -d',' -f1`
LOAD=`cat /proc/loadavg |awk '{print $2}' | cut -d'.' -f1`
if [ "$UPTIME" -gt 600 ]
then
if [ "$WAIT" -gt 50 ]
then
if [ "$LOAD" -gt 4 ]
then
#action to take (reboot, restart service, save state sleep retry)
MAIL_TXT="System Status: iowait:"$WAIT" loadavg5:"$LOAD" uptime:"$UPTIME"!"
echo $MAIL_TXT | mail -s "Server Alert Status" "mymail#foe.foe"
/etc/init.d/httpd stop
# /etc/init.d/mysql stop
sleep 10
# /etc/init.d/mysql start
/etc/init.d/httpd start
fi
fi
fi
CentOS release 6.8 (Final) 2.6.32-642.13.1.el6.x86_64
Normally, you'd need to use something other than native shell math, as described in BashFAQ #22. However, since you're comparing to integers, this is easy: You can just truncate at the decimal point.
[ "${UPTIME%%.*}" -gt 600 ] # truncates your UPTIME at the decimal point
[ "${WAIT%%.*}" -gt 50 ] # likewise

Integer expression expected (Bash)

I'm trying to create a simple script that checks if the CPU Usage is at a certain level. I have a Raspberry Pi for this project.
The only issue I have currently is that I have the variable CPU which is the CPU usage, when the script runs, I get the error
line 25: [: 4.8: integer expression expected
I'm not sure why bash returns this if BASH really doesn't care about int, String, etc. like JAVA does. Found that out here.
Also, I have the if statement: if $CPU -gt 1 only for testing (it's supposed to return true right now)
red='\e[0;31m'
yellow='\e[1;33m'
NC='\e[0m' # No Color
echo -e "${NC}Starting Server!${NC}"
echo -e "${red}Errors in red!${NC}"
echo -e "${yellow}Info in yellow!${NC}"
sleep 1
echo -e "\n\n"
##CPU USAGE STUFF
echo -e "${yellow}Current CPU Usage:"
CPU=$(top -bn1 | grep "Cpu(s)" | \
sed "s/.*, *\([0-9.]*\)%* id.*/\1/" | \
awk '{print 100 - $1""}')
echo $CPU %
echo -e "${NC}**********${NC}"
cd /root/mc_server/
sleep 1
##CPU USAGE LOOP CHECKER
while :
do
sleep 5
echo $CPU
if [ $CPU -gt 1 ]
then
echo -e "${red}ALERT! CPU Usage is TOO HIGH!${red}"
fi
done
##
##java -Xmx400M -jar bukkit.jar -o true
The issue is that 4.8 is an non-integer value.
You can use bc to deal with non-integer values like so:
if [[ $(echo "$CPU > 1" | bc -l) -eq 1 ]];
it will return boolean expressions as either 1 for true or 0 for false.

Why do this sample script, keep outputting error near token?

enter image description hereI was trying to see how a shell scripts work and how to run them, so I toke some sample code from a book I picked up from the library called "Wicked Cool Shell Scripts"
I re wrote the code verbatim, but I'm getting an error from Linux, which I compiled the code on saying:
'd.sh: line 3: syntax error near unexpected token `{
'd.sh: line 3:`gmk() {
Before this I had the curly bracket on the newline but I was still getting :
'd.sh: line 3: syntax error near unexpected token
'd.sh: line 3:`gmk()
#!/bin/sh
#format directory- outputs a formatted directory listing
gmk()
{
#Give input in Kb, output converted to Kb, Mb, or Gb for best output format
if [$1 -ge 1000000]; then
echo "$(scriptbc -p 2 $1/1000000)Gb"
elif [$1 - ge 1000]; then
echo "$$(scriptbc -p 2 $1/1000)Mb"
else
echo "${1}Kb"
fi
}
if [$# -gt 1] ; then
echo "Usage: $0 [dirname]" >&2; exit 1
elif [$# -eq 1] ; then
cd "$#"
fi
for file in *
do
if [-d "$file"] ; then
size = $(ls "$file"|wc -l|sed 's/[^[:digit:]]//g')
elif [$size -eq 1] ; then
echo "$file ($size entry)|"
else
echo "$file ($size entries)|"
fi
else
size ="$(ls -sk "$file" | awk '{print $1}')"
echo "$file ($(gmk $size))|"
fi
done | \
sed 's/ /^^^/g' |\
xargs -n 2 |\
sed 's/\^\^\^/ /g' | \
awk -F\| '{ printf "%39s %-39s\n", $1, $2}'
exit 0
if [$#-gt 1]; then
echo "Usage :$0 [dirname]" >&2; exit 1
elif [$# -eq 1]; then
cd "$#"
fi
for file in *
do
if [ -d "$file" ] ; then
size =$(ls "$file" | wc -l | sed 's/[^[:digit:]]//g')
if [ $size -eq 1 ] ; then
echo "$file ($size entry)|"
else
echo "$file ($size entries)|"
fi
else
size ="$(ls -sk "$file" | awk '{print $1}')"
echo "$file ($(convert $size))|"
fi
done | \
sed 's/ /^^^/g' | \
xargs -n 2 | \
sed 's/\^\^\^/ /g' | \
awk -F\| '{ printf "%-39s %-39s\n", $1, $2 }'
exit 0
sh is very sensitive to spaces. In particular assignment (no spaces around =) and testing (must have spaces inside the [ ]).
This version runs, although fails on my machine due to the lack of scriptbc.
You put an elsif in a spot where it was supposed to be if.
Be careful of column alignment between starts and ends. If you mismatch them it will easily lead you astray in thinking about how this works.
Also, adding a set -x near the top of a script is a very good way of debugging what it is doing - it will cause the interpreter to output each line it is about to run before it does.
#!/bin/sh
#format directory- outputs a formatted directory listing
gmk()
{
#Give input in Kb, output converted to Kb, Mb, or Gb for best output format
if [ $1 -ge 1000000 ]; then
echo "$(scriptbc -p 2 $1/1000000)Gb"
elif [ $1 -ge 1000 ]; then
echo "$(scriptbc -p 2 $1/1000)Mb"
else
echo "${1}Kb"
fi
}
if [ $# -gt 1 ] ; then
echo "Usage: $0 [dirname]" >&2; exit 1
elif [ $# -eq 1 ] ; then
cd "$#"
fi
for file in *
do
if [ -d "$file" ] ; then
size=$(ls "$file"|wc -l|sed 's/[^[:digit:]]//g')
if [ $size -eq 1 ] ; then
echo "$file ($size entry)|"
else
echo "$file ($size entries)|"
fi
else
size="$(ls -sk "$file" | awk '{print $1}')"
echo "$file ($(gmk $size))|"
fi
done | \
sed 's/ /^^^/g' |\
xargs -n 2 |\
sed 's/\^\^\^/ /g' | \
awk -F\| '{ printf "%39s %-39s\n", $1, $2}'
exit 0
By the way, with respect to the book telling you to modify your PATH variable, that's really a bad idea, depending on what exactly it advised you to do. Just to be clear, never add your current directory to the PATH variable unless you intend on making that directory a permanent location for all of your scripts etc. If you are making this a permanent location for your scripts, make sure you add the location to the END of your PATH variable, not the beginning, otherwise you are creating a major security problem.
Linux and Unix do not add your current location, commonly called your PWD, or present working directory, to the path because someone could create a script called 'ls', for example, which could run something malicious instead of the actual 'ls' command. The proper way to execute something in your PWD, is to prepend it with './' (e.g. ./my_new_script.sh). This basically indicates that you really do want to run something from your PWD. Think of it as telling the shell "right here". The '.' actually represents your current directory, in other words "here".

Grep multiple bash parameters

I'm writing a bash script which shall search in multiple files.
The problem I'm encountering is that I can't egrep an undetermined number of variables passed as parameters to the bash script
I want it to do the following:
Given a random number of parameters. i.e:
./searchline.sh A B C
Do a grep on the first one, and egrep the result with the rest:
grep "A" * | egrep B | egrep C
What I've tried to do is to build a string with the egreps:
for j in "${#:2}";
do
ADDITIONALSEARCH="$ADDITIONALSEARCH | egrep $j";
done
grep "$1" * "$ADDITIONALSEARCH"
But somehow that won't work, it seems like bash is not treating the "egrep" string as an egrep.
Do you guys have any advice?
By the way, as a side note, I'm not able to create any auxiliary file so grep -f is out of the line I guess. Also note, that the number of parameters passed to the bash script is variable, so I can't do egrep "$2" | egrep "$3".
Thanks in advance.
Fernando
You can use recursion here to get required number of pipes:
#!/bin/bash
rec_egrep() {
if [ $# -eq 0 ]; then
exec cat
elif [ $# -eq 1 ]; then
exec egrep "$1"
else
local pat=$1
shift
egrep "$pat" | rec_egrep "$#"
fi
}
first_arg="$1"
shift
grep "$first_arg" * | rec_egrep "$#"
A safe eval can be a good solution:
#!/bin/bash
if [[ $# -gt 0 ]]; then
temp=("grep" "-e" "\"\$1\"" "*")
for (( i = 2; i <= $#; ++i )); do
temp=("${temp[#]}" "|" "egrep" "-e" "\"\$$i\"")
done
eval "${temp[#]}"
fi
To run it:
bash script.sh A B C

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