SSH from Host A to a few hosts (only one listed below right now) using the SSH Key I generated and then go to a specific file, grep for a specific word with a date of yesterday .. then I want to email this output to myself.
It is sending an email but it is giving me the command as opposed to the output from the command.
#!/bin/bash
HOST="XXXXXXXXXXXXXXXXXX, XXXXXXXXXXXXX"
DATE=$(date -d "yesterday")
INVALID=' cat /xxx/xxx/xxxxx | grep 'WORD' | sed 's/$/.\n/g' | grep "$DATE"'
COUNT=$(echo "$INVALID" | wc -c)
for x in $HOSTS
do
ssh BLA#"$x" $COUNT
if [ "$COUNT" -gt 1 ];
then
EMAILTEXT=""
if [ "$COUNT" -gt 1 ];
then
EMAILTEXT="$INVALID"
fi
fi
done | echo -e "$EMAILTEXT" | mail XXXXXXXXXXX.com
This isn't properly an attempt to answer your question, but I think you should be aware of some fundamental problems with your code.
INVALID=' cat /xxx/xxx/xxxxx | grep 'WORD' | sed 's/$/.\n/g' | grep "$DATE"'
This assigns a simple string to the variable INVALID. Because of quoting issues, s/$/.\n/g is not quoted at all, and will probably be mangled by the shell. (You cannot nest single quotes -- the first single-quoted string extends from the first quote to the next one, and then WORD is outside of any quotes, followed by the next single-quoted string, etc.)
If your intent is to execute this as a command at this point, you are looking for a command substitution; with the multiple layers of uselessness peeled off, perhaps something like
INVALID=$(sed -n -e '/WORD/!d' -e "/$DATE/s/$/./p" /xxx/xxx/xxxx)
which looks for a line matching WORD and $DATE and prints the match with a dot appended at the end -- I believe that's what your code boils down to, but without further insights into what this code is supposed to do, it's impossible to tell if this is what you actually need.
COUNT=$(echo "$INVALID" | wc -c)
This assigns a number to $COUNT. With your static definition of INVALID, the number will always be 62; but I guess that's not actually what you want here.
for x in $HOSTS
do
ssh BLA#"$x" $COUNT
This attempts to execute that number as a command on a number of remote hosts (except the loop is over HOSTS and the variable containing the hosts is named just HOST). This cannot possibly be useful, unless you have a battery of commands named as natural numbers which do something useful on these remote hosts; but I think it's safe to assume that that is not what is supposed to be going on here (and if it was, it would absolutely be necessary to explain this in your question).
if [ "$COUNT" -gt 1 ];
then
EMAILTEXT=""
if [ "$COUNT" -gt 1 ];
then
EMAILTEXT="$INVALID"
fi
fi
So EMAILTEXT is either an empty string or the value of INVALID. You assigned it to be a static string above, which is probably the source of your immediate question. But even if it was somehow assigned to a command on the local host, why do you need to visit remote hosts and execute something there? Or is your intent actually to execute the command on each remote host and obtain the output?
done | echo -e "$EMAILTEXT" | mail XXXXXXXXXXX.com
Piping into echo makes no sense at all, because it does not read its standard input. You should probably just have a newline after done; though a possibly more useful arrangement would be to have your loop produce output which we then pipe to mail.
Purely speculatively, perhaps something like the following is what you actually want.
for host in $HOSTS; do
ssh BLA#"$host" sed -n -e '/WORD/!d' -e "/$DATE/s/$/./p" /xxx/xxx/xxxx |
grep . || echo INVALID
done | mail XXXXXXXXXXX.com
If you want to check that there is strictly more than one line of output (which is what the -gt 1 suggests) then this may need to be a little bit more complicated.
Your command substitution is not working. You should read up on how it works but here are the problem lines:
COUNT=$(echo "$INVALID" | wc -c)
[...]
ssh BLA#"$x" $COUNT
should be:
COUNT_CMD="'${INVALID} | wc -c'"
[...]
COUNT=$(ssh BLA#"$x" $COUNT_CMD)
This inserts the value of $INVALID into the string, and puts the whole thing in single quotes. The single quotes are necessary for the ssh call so the pipes aren't evaluated in the script but on the remote host. (COUNT is changed to COUNT_CMD for readability/clarity.)
EDIT:
I misread the question and have corrected my answer.
Related
I'm trying to search for multiple domain names availability with this script but it doesn't work, where's the mistake? thanks
#!/bin/bash
WEB=('madmane1' 'madmane2' 'madmane3' 'madmane4' 'madmane5' 'madmane6' 'madmane7' 'madmane8' 'madmane9')
ELEMENTS=${#WEB[#]}
for (( i=0;i<$ELEMENTS;i++)); do
whois ${WEB[${i}]}$'.com' | egrep -q \
'^No match|^NOT FOUND|^Not fo|AVAILABLE|^No Data Fou|has not been regi|No entri'
if [ $? -eq 0 ]; then
echo "${WEB[${i}]}$'.com' : available"
fi
done
here's the error:
line 9: ^No match|^NOT FOUND|^Not fo|AVAILABLE|^No Data Fou|has not been regi|No entri: command not found
Assigning stuff to an array and then wrecking it by assigning it to a string without quoting seems like the main mistake here, though it's not the reason you are getting a syntax error.
You also want to avoid testing ”$?” to see if a command succeeded or not, an anti-pattern
See also Correct Bash and shell script variable capitalization
The reason for the error message seems to be a space after the backslash, so you are escaping the space instead of the newline, and thus the shell (in some sense correctly) parses the next line as a new command.
#!/bin/bash
web=('madmane1' 'madmane2' 'madmane3' 'madmane4' 'madmane5' 'madmane6' 'madmane7' 'madmane8' 'madmane9')
for domain in "${web[#]}"; do
if whois "$domain.com" |
grep -Eq '^No match|^NOT FOUND|^Not fo|AVAILABLE|^No Data Fou|has not been regi|No entri'
then
echo "$domain.com: available"
fi
done
Going forward, probably try http://shellcheck.net/ before asking for human assistance.
I think I fixed the problem with https://www.shellcheck.net/
here it is now:
#!/bin/bash
WEB=('madmane1' 'madmane2' 'madmane3' 'madmane4' 'madmane5' 'madmane6' 'madmane7' 'madmane8' 'madmane9')
ELEMENTS=${#WEB[#]}
for (( i=0;i<$ELEMENTS;i++)); do
whois "${WEB[${i}]}"$'.com' | grep -E \
'^No match|^NOT FOUND|^Not fo|AVAILABLE|^No Data Fou|has not been regi|No entri'
if [ $? -eq 0 ]; then
echo "${WEB[${i}]}$'.com' : available"
fi
done
I am new to shell script , i want to write a script to monitor CPU usage and if the CPU usage reaches a threshold it should print the CPU usage by top command ,here is my script , which is giving me error bad number and also not storing any value in the log files
while sleep 1;do if [ "$(top -n1 | grep -i ^cpu | awk '{print $2}')">>sy.log - ge "$Threshold" ]; then echo "$(top -n1)">>sys.log;fi;done
Your script HAS to be indented and stored to a file, especially if you are new to shell !
#!/bin/sh
while sleep 1
do
if [ "$(top -n1 | grep -i ^cpu | awk '{print $2}')">>sy.log - ge "$Threshold" ]
then
echo "$(top -n1)" >> sys.log
fi
done
Your condition looks a bit odd. It may work, but it looks really complex. Store intermediate results in variables, and evaluate them.
Then, you will immediately see the syntax error on the “-ge”.
You HAVE to store logfiles within an absolute path for security reasons. Use variables to simplify the reading.
#!/bin/sh
LOGFILE=/absolute_path/sy.log
WHOLEFILE=/absolute_path/sys.log
Thresold=80
while sleep 1
do
TOP="$(top -n1)"
CPU="$(echo $TOP | grep -i ^cpu | awk '{print $2}')"
echo $CPU >> $LOGFILE
if [ "$CPU" -ge "$Threshold" ] ; then
echo "$TOP" >> $WHOLEFILE
fi
done
You have a couple of errors.
If you write output to sy.log with a redirection then that output is no longer available to the shell. You can work around this with tee.
The dash before -ge must not be followed by a space.
Also, a few stylistic remarks:
grep x | awk '{y}' is a useless use of grep; this can usefully and more economically (as well as more elegantly) be rewritten as awk '/x/{y}'
echo "$(command)" is a useless use of echo -- not a deal-breaker, but you simply want command; there is no need to capture what it prints to standard output just so you can print that text to standard output.
If you are going to capture the output of top -n 1 anyway, there is no need really to run it twice.
Further notes:
If you know the capitalization of the field you want to extract, maybe you don't need to search case-insensitively. (I could not find a version of top which prints a CPU prefix with the load in the second field -- it the expression really correct?)
The shell only supports integer arithmetic. Is this a bug? Maybe you want to use Awk (which has floating-point support) to perform the comparison? This also allows for a moderately tricky refactoring. We make Awk output an exit code of 1 if the comparison fails, and use that as the condition for the if.
#!/bin/sh
while sleep 1
do
if top=$(top -n 1 |
awk -v thres="$Threshold" '1; # print every line
tolower($1) ~ /^cpu/ { print $2 >>"sy.log";
exitcode = ($2 >= thres ? 0 : 1) }
END { exit exitcode }')
then
echo "$top" >>sys.log
fi
done
Do you really mean to have two log files with nearly the same name, or is that a typo? Including a time stamp in the log might be useful both for troubleshooting and for actually using the log files.
I need to assign the output of a command to a variable. The command I tried is:
#!/bin/bash
JAVA_PROCESSES=`jps -vl | grep -v 'sun.tools.jps.Jps' | grep -v 'hudson.remoting.jnlp.Main' | grep -v grep`
NUMBER_OF_JAVA_PROCESSES=`echo $JAVA_PROCESSES | wc -l`
echo $NUMBER_OF_JAVA_PROCESSES
echo $JAVA_PROCESSES
..
When I tried as in above, all java processes grepped are assigned to JAVA_PROCESSES variable in one line. Processes are not separated by new line. Therefore $NUMBER_OF_JAVA_PROCESSES always give 1 for me.
Also $NUMBER_OF_JAVA_PROCESSES show 1 even no processes are assigned to JAVA_PROCESSES due to the empty line in $JAVA_PROCESSES.
Please suggest a way to assign grepped processes separated by new line.
If the main thing you want is to know whether or not you got any at all, you could just test if the variable is empty:
java_procs=$(jps -vl | grep -v 'sun.tools.jps.Jps' | grep -v 'hudson.remoting.jnlp.Main' | grep -v grep)
if [ -z "$java_procs" ]; then
echo "No processes"
fi
Also, we can simplify the grep by using extended regex and just needing a single processes:
java_procs=$(jps -vl | grep -Ev 'sun.tools.jps.Jps|hudson.remoting.jnlp.Main|grep')
Assuming none of the lines output by jps can contain linebreaks themselves, we could get the count after that if we need it:
num_procs=$(printf '%s\n' "$java_procs" | wc -l)
The main problem you were running into is that you weren't quoting your variable, so echo $JAVA_PROCESSES was being expanded and then subject to word splitting, so your newlines were being "eaten" by the shell. You'd always have only one line which would be a space separated list of all the words in your JAVA_PROCESSES variable. To protect from word splitting you can quote the variable, as I did in my code above.
echo will also always add a line break at the end, which is good sometimes, and not so good sometimes, but you should be aware of it happening (that's why you would always get a count of 1 even when there were no processes).
I always write some magic numbers in my interactive shells and shell scripts.
For instance, If I want to list my users's names and shells, I'll write
cut --delimiter=: --fields=1,7 /etc/passwd
There exist two magic-numbers 1,7. And there are more and more magic-numbers in other circumstances.
Question
How to avoid magic-numbers in interactive shells and shell scripts?
Supplementary background
Our teacher told us using cut -d: -f1,7 /etc/passwd. But for new linux-users, they don't konw what's meaning of d,f,1,7.(not just for new linux-users，the whole system has so many configuration files that it is not easy for a person to remember every magic-numbers)
So, in interactive shells, we can use --delimiter, --fields,and the bash repl(or zsh,fish) has good tab completion to it.
How about the 1 and 7? In shell scripts, It's a good method to declare some const variables like LoginField=1 and ShellField=7 after reading the man 5 passwd. But when some one is writing in the interactive shells, it's not a good idea to open a new window and search the constants of LoginField=1,ShellField=7 and define it. how to using some thing like tab completion to simplify operations?
Use variables:
LoginField=1 ShellField=7
cut --delimiter=: --fields="$LoginField,$ShellField" /etc/passwd
Just like in other languages - by using variables. Example:
$ username_column=1
$ shell_column=7
$ cut --delimiter=: --fields="$username_column","$shell_column" /etc/passwd
The variables may be defined at the top of the script so that can be
easily modified or they can be set in an external config-like file
shared by multiple scripts.
The classic way to parse /etc/passwd is to read each column into an appropriately named variable:
while IFS=: read name passwd uid gid gecos home shell _; do
...
done < /etc/passwd
Use export:
export field_param="1,7"
(you can put it .bashrc file to have configured each time shell session is started). This export can be part of .sh script. It's a good practice to put them in the head/top of the file.
Then:
cut --delimiter=: --fields=$field_param /etc/passwd
This way you will need to edit the magic number in the only location.
Continuing from my comment, it's hard to tell exactly what you are asking. If you just want to give meaningful variable names, then do as shown in the other answers.
If however you want to be able to specify which fields are passed to cut from the command line, then you can use the positional parameters $1 and $2 to pass those values into your script.
You need to validate that two inputs are given and that both are integers. You can do that with a few simple tests, e.g.
#!/bin/bash
[ -n "$1" ] && [ -n "$2" ] || { ## validate 2 parameters given
printf "error: insufficient input\nusage: %s field1 field2\n" "${0##*/}"
exit 1
}
## validate both inputs are integer values
[ "$1" -eq "$1" >/dev/null 2>&1 ] || {
printf "error: field1 not integer value '%s'.\n" "$1"
exit 1
}
[ "$2" -eq "$2" >/dev/null 2>&1 ] || {
printf "error: field2 not integer value '%s'.\n" "$2"
exit 1
}
cut --delimiter=: --fields=$1,$2 /etc/passwd
Example Use/Output
$ bash fields.sh
error: insufficient input
usage: fields.sh field1 field2
$ bash fields.sh 1 d
error: field2 not integer value 'd'.
$ bash fields.sh 1 7
root:/bin/bash
bin:/usr/bin/nologin
daemon:/usr/bin/nologin
mail:/usr/bin/nologin
ftp:/usr/bin/nologin
http:/usr/bin/nologin
uuidd:/usr/bin/nologin
dbus:/usr/bin/nologin
nobody:/usr/bin/nologin
systemd-journal-gateway:/usr/bin/nologin
systemd-timesync:/usr/bin/nologin
systemd-network:/usr/bin/nologin
systemd-bus-proxy:/usr/bin/nologin
<snip>
Or if you choose to look at fields 1 and 3, then all you need do is pass those as the parameters, e.g.
$ bash fields.sh 1 3
root:0
bin:1
daemon:2
mail:8
ftp:14
http:33
uuidd:68
dbus:81
nobody:99
systemd-journal-gateway:191
systemd-timesync:192
systemd-network:193
systemd-bus-proxy:194
<snip>
Look things over and let me know if you have further questions.
Scraping the output of man 5 passwd for human-readable header names:
declare $(man 5 passwd |
sed -n '/^\s*·\s*/{s/^\s*·\s*//;y/ /_/;p}' |
sed -n 'p;=' | paste -d= - - )
See "how it works" below for what that does, then run:
cut --delimiter=: \
--fields=${login_name},${optional_user_command_interpreter} /etc/passwd
Which outputs the specified /etc/passwd fields.
How it works.
The man page describing /etc/passwd contains a bullet list of header names. Use GNU sed to find the bullets (·) and leading whitespace, then remove the bullets and whitespace, replace the remaining spaces with underlines; a 2nd instance of sed provides fresh line numbers, then paste the header names to the line numbers, with a = between:
man 5 passwd |
sed -n '/^\s*·\s*/{s/^\s*·\s*//;y/ /_/;p}' |
sed -n 'p;=' | paste -d= - -
Outputs:
login_name=1
optional_encrypted_password=2
numerical_user_ID=3
numerical_group_ID=4
user_name_or_comment_field=5
user_home_directory=6
optional_user_command_interpreter=7
And declare makes those active in the current shell.
I just wrote a ping sweep script in Bash this morning, and guess what: it's not working. Can you please check what it is that I'm missing.
Here's the script:
for i in `seq 1 255`
do
if ["$(ping -c1 -W1 -n 192.168.1.$i | grep '%' | cut -d',' -f3 | cut -d' ' -f2)" -eq "0%"]
then echo "Host live"
else echo "Host down"
fi
done
And here's the error:
bash: [0%: command not found
Host down
bash: [100%: command not found
Host down
My purpose is to make a ping sweep program which scans the range 192.168.1.1-255 and it notifies the host's status. I know about nmap but just wanted to learn skills in Bash so I made this one. Please try to tell what the error meant. I mean to what command it's referring "command not found"?
The ping command returns error code if there was any problem, so you do not need to parse the output:
for i in {1..255}
do
if ping -c1 -W1 -n "192.168.1.$i"
then
echo 'Host live'
else
echo 'Host down'
fi
done
Primary diagnosis
The [ command needs a space after its name, just like the rm command needs a space after its name and the ls command does, and … The [ command also requires its last argument to be ], spelled thus, so there needs to be a space before that, too.
You have:
if ["$(ping -c1 -W1 -n 192.168.1.$i | grep '%' | cut -d',' -f3 | cut -d' ' -f2)" -eq "0%"]
At minimum, you need:
if [ "$(ping -c1 -W1 -n 192.168.1.$i | grep '%' | cut -d',' -f3 | cut -d' ' -f2)" -eq "0%" ]
Secondary issues
Note that 'at minimum' means, amongst other things, that I've not spent time analyzing why you are executing the complex sequence of 4 commands in the test condition, or looked for ways to cut that down to two (using grep and cut twice suggests that sed or a more powerful tool would be better). I griped about the formatting in the original version of the question, where the loop (it isn't a nested loop, incidentally — or it isn't in the code shown) was all on one line thanks to Bash flattening it in history. My version of the code would have far fewer semicolons in it, for example. The -eq operator in [ is for testing the equality of numbers (the converse convention applies in Perl, where eq is for testing strings and == tests numbers). Note that POSIX standard [ (aka test) does not support == as a synonym for =, though Bash does. It isn't entirely clear that "0%" is OK as an argument for numeric comparison. Many programs would not object — the zero can be converted and the residue doesn't matter; others might decide legitimately to complain that the whole string could not be converted, so it is erroneous. Careful code wouldn't risk the disconnect.
See Steven Penny's answer for a more thorough rewrite of the code. My answer remains a valid diagnosis of the immediate problem of not being able to find commands named [0% and [100%.