I want to create a script that,depending on the distribution,runs a set of commands(in this example I want to check for Ubuntu and Centos). I've made a basic if-else statement in the script,but im new to bash and I can't understand why it doesn't work. Here's the code:
a= lsb_release -i | awk -F " " '{print $3}'
if [ "$a"=="Ubuntu" ]; then
echo "$a"
else
echo "Not ubuntu"
fi
Thanks in advance!
Related
I am getting an output from a shell command, and want to incorporate the first column of a matching line into a second command. Here is what I have, and it works:
kubectl get pods -n system | while read string; do
if [[ "$string" == my-pod-* && "$string" == *Running* ]]; then
# echo $string
read -ra ADDR <<< "$string"
echo
echo "--- Reading logs for ${ADDR[0]} ---"
# desired output: kubectl -n system logs my-pod-123 --tail=5 -f
kubectl -n system logs ${ADDR[0]} --tail=5 -f
fi
done
the output from first command would look something like this:
name status namespace running
my-pod-123 Running system 4h31m #<<I want this one
another-pod-5 Running system 5h15m
my-pod-023 Terminating system 8h05m
given that the output will contain only one match, is there a shorter way to do this without looping like this? Thanks in advance for helping me improve my Bash skills as this seems very clumsy.
You may use awk like this:
name=$(kubectl get pods -n system | awk '/^my-pod.*Running/{print $1}')
[[ -n $name ]] && kubectl -n system logs "$name" --tail=5 -f
awk command will match pattern my-pod.*Running at the start of a line and if it is found then it will print first column. We store that in variable name.
If $name is not empty then we call kubectl -n system logs using that value.
How about grep?
wanted=$(kubectl get pods -n system | grep 'my-pod-.*Running')
Can do error checking at the same time:
if ! wanted=$(kubectl get pods -n system | grep 'my-pod-.*Running'); then
echo "Error: no running my-pods" >&2
fi
What am I doing wrong. I'm sure what I'm attempting to do should be clear to everyone.
#/usr/bin/env sh
echo -e "What VM?"
read vname
if [ '`VboxManage list vms | grep -c "$vname"`' != 0 ]; then
echo exists
fi
Anyone have suggestions. Pretty much it should tell me if the VM exist or not.
First your shebang is wrong.
Try this code
#!/usr/bin/env sh
echo -e "What VM?"
read -r vname
if [ "$(VboxManage list vms | grep -c "$vname")" != 0 ]; then
echo exists
fi
EDIT: Working script below
I have used this site MANY times to get answers, but I am a little stumped with this.
I am tasked with writing a script, in bash, to log into roughly 2000 Unix servers (Solaris, AIX, Linux) and check the size of OS filesystems, most notable /var /usr /opt.
I have set some variables, which may be where I am going wrong right off the bat.
1.) First I am connecting to another server that has a list of all hosts in the infrastructure. Then I parse this data with some sed commands to get a list I can use properly
1.) Then I do a ping test, to see if the server is alive. If the server is decom. The idea behind this, is if the server is not pingable, I don't want it being reported on, or any attempt to be made to connect to it, as it is just wasting time. I feel I am doing this wrong, but don't know how to do it corectly (a re-occurring theme you will here in this post lol)
If any FS is over 80% mark, then it should output to a text file with the servername, filesystem, size on one line <== very important for me
If the FS is under 80% full, then I don't want it in my output, it can me omitted completely.
I have created something that I will post below, and am hoping to get some help in figuring out where I am going wrong. I am very new to bash scripting, but have experience as a Unix admin (i have never been good at scripting).
Can anyone provide some direction and teach me where I am going wrong?
I will upload my script that i can confirm is working hopefully tomorrow. thanks everyone for your input in this!
Here is my "disk usage" linux script, i hope that help you.
#!/bin/sh
df -H | awk '{ print $5 " " $6 }' | while read output;
do
echo $output
usep=$(echo $output | awk '{ print $1}' | cut -d'%' -f1 )
partition=$(echo $output | awk '{ print $2 }' )
if [ $usep -ge 90 ]; then
echo "Running out of space \"$partition ($usep%)\" on $(hostname) as on $(date)" |
mail -s "Warning! There is no space on the disk: $usep%" root#domain.com
fi
done
Some trouble is here:
ping -c 1 -W 3 $i > /dev/null 2>&1
if [ $? -ne 0 ]; then
echo "$i is offline" >> $LOG
fi
You need a continue statement inside that if. Your program isn't really treating non-pingable hosts differently, just logging they're not pingable.
Okay, now I'm looking a little deeper, and there's more naive stuff in here. These shouldn't work:
SOLVARFS=$(df -h /var |cut -f5 |grep -v capacity |awk '{print $5}')
SOLUSRFS=$(df -h /usr |cut -f5 |grep -v capacity |awk '{print $5}')
SOLOPTFS=$(df -h /opt |cut -f5 |grep -v capacity |awk '{print $5}')
etc...
The problem with these lines is, the command substitution gets assigned to the variables before the ssh session happens. So the content of each variable is the command's result on your local system, not the command itself. Since you're doing command substitution around your ssh calls, it might well work just to rewrite these lines as (note the backslash escapes on $5):
SOLVARFS="df -h /var |cut -f5 |grep -v capacity |awk '{print \$5}'"
SOLUSRFS="df -h /usr |cut -f5 |grep -v capacity |awk '{print \$5}'"
SOLOPTFS="df -h /opt |cut -f5 |grep -v capacity |awk '{print \$5}'"
etc...
The part where you're contacting another server has some more stuff to correct. You don't need three if statements per server, and there's no reason to echo anything to /dev/null. Here's a rewrite for the SunOS section. For each directory you're checking, it outputs the host name, the command name (so you can see which dir was being checked), and the result:
if [[ $UNAME = "SunOS" ]]; then
for SSH_COMMAND in SOLVARFS SOLUSRFS SOLOPTFS ; do
RESULT=`ssh -o PasswordAuthentication=no -o BatchMode=yes -o StrictHostKeyChecking=no -o ConnectTimeout=2 GSSAPIAuthentication=no -q $i ${!SSH_COMMAND}`
if ["$RESULT" -gt 80] ; do
echo "$i, $SSH_COMMAND, $RESULT" >> $LOG
fi
done
fi
Note that the ${!BLAH} construction is variable indirection. "Give me the contents of the variable named by BLAH".
Your original script does a bunch of things less-than-optimally. Rather than running an almost-identical block of code for each filesystem and each operating system, the thing to do would be to record the differences in a way that a SINGLE piece of code can iterate over all your objects, adapting as required.
Here's my take on this. Commands should appear ONCE, but
they get run multiple times by loops, and
they get run multiple ways using arrays.
The following script passes lint checks, but obviously this is untested, as I don't have your environment to test in.
You might still want to think about how your logging and notifications work.
#!/bin/bash
# Assign temp file, remove it automatically upon successful exit.
tmpfile=$(mktemp /tmp/${0##*/}.XXXX)
trap "rm '$tmpfile'" 0
#NOW=$(date +"%Y-%m-%d-%T")
NOW=$(date +"%F")
LOG=/usr/scripts/disk_usage/Unix_df_issues-$NOW.txt
printf '' > "$LOG"
# Use variables to refer to commonly accessed files. If you change a name, just do it once.
rawhostlist=all_vms.txt
host_os=${rawhostlist}_OS
# Commonly-used options need only be declared once. Use an array for easier management.
declare -a ssh_opts=()
ssh_opts+=(-o PasswordAuthentication=no)
ssh_opts+=(-o BatchMode=yes)
ssh_opts+=(-o StrictHostKeyChecking=no) # Eliminate prompts on new hosts
ssh_opts+=(-o ConnectTimeout=2) # This should make your `ping` unnecessary.
ssh_opts+=(-o GSSAPIAuthentication=no) # This is default. Do we really need it?
# Note: Associative arrays require Bash 4.x.
declare -A df_opts=(
[SunOS]="-h"
[Linux]="-hP"
[AIX]=""
)
declare -A df_column=(
[SunOS]=5
[Linux]=5
[AIX]=4
)
# Fetch host list from configserver, stripping /^adm/ on the remote end.
ssh "${ssh_opts[#]}" -q configserver "sed 's/^adm//' /reports/*/HOSTNAME" > "$rawhostlist"
# Confirm that our host_os cache is up to date and process any missing hosts.
awk '
NR==FNR { h[$1]; next } # Add everything in rawhostlist to an array...
{ delete h[$1] } # Then remove any entries that exist in host_os.
END {
for (i in h) print i # And print whatever remains.
}' "$rawhostlist" "$host_os" |
while read h; do
printf '%s\t%s\n' "$h" $(ssh "$h" "${ssh_opts[#]}" -q uname -s)
done >> "$host_os"
# Next, step through the host list and collect data.
while read host os; do
ssh "${ssh_opts[#]}" "$host" df "${df_opts[$os]}" /var /usr /opt |
awk -v column="${df_column[$os]}" -v host="$host" 'NR>1 { print host,$1,$column }'
)
done < "$host_os" > "$tmpfile"
# Now that we have all our data, check for warning/critical levels.
while read host filesystem usage; do
if [ "$usage" -gt 80 ]; then
status="CRITICAL"
elif [ "$usage" -gt 70 ]; then
status="WARNING"
else
continue
fi
# Log our results to our log file, AND send them to stderr.
printf "[%s] %s: %s:%s at %d%%\n" "$(date +"%F %T")" "$status" "$host" "$filesystem" "$usage" | tee -a "$LOG" >&2
done < "$tmpfile"
# Email and record our results.
if [ -s "$LOG" ]; then
mail -s "Daily Unix /var Report - $NOW" unixsystems#examplle.com < "$LOG"
mv "$LOG" /var/log/vm_reports/
fi
Consider this example code. If you like the way it looks, your next task is to debug it, or open new questions for parts that you're having trouble debugging. :-)
I am trying to learn shell script. So sorry if my question is so simple.
I am having a file called one.txt and if either strings 1.2 or 1.3 is present in the string then I have to display the success message else the failure message.
The code I tried is follows,
#!/bin/bash
echo "checking"
if grep -q 1.2 /root/one | grep -q 1.3 /root/one; then
echo " vetri Your NAC version"
fi
What I am doing wrong here ?
You can also include the OR in your grep pattern like so:
grep '1.2\|1.3' /root/one
details here
Update:
as twalberg pointed out in the comment, my answer was not precise enough. The better pattern is:
grep '1\.2\|1\.3' /root/one
Or even better, because more compact:
grep '1\.[23]' /root/one
You have to use ||
#!/bin/bash
echo "checking"
if grep -q 1.2 /root/one || grep -q 1.3 /root/one; then
echo " vetri Your NAC version"
fi
Single | operator is called pipe. It will pass the output of the command before | to the command after |.
It is better to join these these greps with | (OR operator):
grep '1.2\|1.3'
or
grep -E '1.2|1.3'
I guess the easier way to do this is to create a variable to check the count of occurrences:
#!/bin/bash
echo "checking"
CHECK=`egrep -c '1\.(2|3)' /root/one`
if [ "$CHECK" -gt 0 ]; then
echo "vetri Your NAC version"
fi
I run bash scripts from time to time on my servers, I am trying to write a script that monitors log folders and compress log files if folder exceeds defined capacity. I know there are better ways of doing what I am currently trying to do, your suggestions are more than welcome. The script below is throwing an error "unexpected end of file" .Below is my script.
dir_base=$1
size_ok=5000000
cd $dir_base
curr_size=du -s -D | awk '{print $1}' | sed 's/%//g' zipname=archivedate +%Y%m%d
if (( $curr_size > $size_ok ))
then
echo "Compressing and archiving files, Logs folder has grown above 5G"
echo "oldest to newest selected."
targfiles=( `ls -1rt` )
echo "rocess files."
for tfile in ${targfiles[#]}
do
let `du -s -D | awk '{print $1}' | sed 's/%//g' | tail -1`
if [ $curr_size -lt $size_ok ];
then
echo "$size_ok has been reached. Stopping processes"
break
else if [ $curr_size -gt $size_ok ];
then
zip -r $zipname $tfile
rm -f $tfile
echo "Added ' $tfile ' to archive'date +%Y%m%d`'.zip and removed"
else [ $curr_size -le $size_ok ];
echo "files in $dir_base are less than 5G, not archiving"
fi
Look into logrotate. Here is an example of putting it to use.
With what you give us, you lack a "done" to end the for loop and a "fi" to end the main if. Please reformat your code and You will get more precise answers ...
EDIT :
Looking at your reformatted script, it is as said : The "unexpected end of file" comes from the fact you have not closed your "for" loop neither your "if"
As it seems that you mimick the logrotate behaviour, check it as suggested by #Hank...
my2c
My du -s -D does not show % sign. So you can just do.
curr_size=$(du -s -D)
set -- $curr_size
curr_size=$1
saves you a few overheads instead of du -s -D | awk '{print $1}' | sed 's/%//g.
If it does show % sign, you can get rid of it like this
du -s -D | awk '{print $1+0}'. No need to use sed.
Use $() syntax instead of backticks whenever possible
For targfiles=(ls -1rt) , you can omit the -1. So it can be
targfiles=( $(ls -rt) )
Use quotes around your variables whenever possible. eg "$zipname" , "$tfile"