Calculation Using Variable Inside Variable

Hello all,
I am trying to execute Code:

ssh $a@$b mkdir abc

in a shell script where, a and b are variables
a=username and b=server.ip
It is giving me an error Quote:
ssh connect to host port 22 connection refused
why am I getting the error?? ssh does not accept variables? Can anyone help.
Thanks in Advance

Hi,

I've used unix before, but have just started to play with CYGWIN (1.1.3) on windows XP (32 bit). I'm having trouble getting 'echo' to behave as I would expect.

I've created a script called runstuff which contains these lines....
Code:

#!/bin/bash
# This line works as expected....
echo "the user is <$USER> and the hostname is <$HOSTNAME>"
MYVAR1=bill
MYVAR2=fred
# This lines doesn't.....
echo "my first variable is<$MYVAR1> and my second is <$MYVAR2>"

The output I get is this...
Quote:
$ runstuff
the user is <Mike> and the hostname is <MikesLaptop>
> and my second is <fredl

In the first echo statement it is just echoing a couple of external variables - this works as expected. In the 2nd echo example the two variables are internal, but the displayed output isn't what I'd expect, my guess is that the first part of the output "my first variable is <bill" has somehow been overwritten by the remainder of the string. Or am I missing something?

I have tried exporting the variables, and I've experimented with wrapping them in quotes, but the results are always the same.

Any help gratefully received.

Hi,
I have a query. How to print sum of two user defined variables. let us take var1 is 6 and var2 is 4. sum should dispay 10 on terminal.

I want to write a Python script. In order to write it I need to figure out how to access the values associated with my signal level and bit rate.

If I use the following command

Code:

iwconfig | grep 'Signal level'

I get:

eth0 no wireless extensions.

lo no wireless extensions.

Link Quality=70/70 Signal level= -38 dBm


Obviously, I don't want Signal level. I want whatever it happens to be. In this case, it happens to be -38. Ditto Bit Rate...How do I grab -38 from the command line?

Hi,
Someone could help me with these sentence?
Code:

per=`print "scale=2; $sum/$count" | bc`

It says me:
Code:

(standard_in) 1: parse error

Why?

For some reason this statement reports "FALSE" when in fact it shouldn't. Any idea why?

Code:

#!/bin/bash

var1=$(nc -dvzw5 thebes.openshells.net 22)
var2='Connection to thebes.openshells.net 22 port [tcp/ssh] succeeded!'
if [ "$var1" = "$var2" ]; then
echo TRUE
else
echo FALSE
fi

Hi all,

Been reading on stdin, stdout and stderr and encounter 2 questions, hope gurus here can advise.

0 = stdin
1 = stdout
2 = stderr

Code:

Sun Dec 21 03:53:42 SGT 2014 > cat test5.sh
#!/bin/bash

echo "Please enter value for name :"
read name
echo "Your name is $name."

echo "Next echo will be a syntax error"
ehco

Code:

Sun Dec 21 03:53:46 SGT 2014 > test5.sh 1> output.txt 2> error.txt
Noob

Sun Dec 21 03:54:56 SGT 2014 > cat output.txt
Please enter value for name :
Your name is Noob.
Next echo will be a syntax error

Sun Dec 21 03:55:23 SGT 2014 > cat error.txt
/home/alan/scripts/test5.sh: line 8: ehco: command not found
Sun Dec 21 03:55:26 SGT 2014 >

Which so far all is good and the correct way to output everything including error to a single file is

Code:

Sun Dec 21 03:59:14 SGT 2014 > test5.sh > output.txt 2>&1

Q1) How is a command being interpreted in linux , the sequence in which it is interpreted ? from left to right ? right to left ?

Shouldn't it be

Code:

test5.sh 2>&1 1>output.txt 
or 
test5.sh 2>&1>output.txt ?

Regards,
Noob

I have the following code to extract two dates using awk, which are then read into two awk variables new and old respectively.
Each dates on the html file pulled with curl request is in this format:
2015-04-06 09:40:37
And two are being extracted
However the strings are being split on white space within the date strings. I tried changing OFS to ',', but it was still splitting incorrectly.
Code:

read dateStrNew dateStrOld < <(curl -k -q "$curl_call" | html2text | gawk '/Newest Sequence/ { new=$3" "$4 }/Oldest Sequence/ \
 {old=$3" "$4}END {OFS=","; print new,old }')  //new = date, old = date

Both parts of the date are being assigned to each variable using $3 and $4, then the space needs to be added back in so that the string can be used afterwards with a date command.

I just can't work out what is wrong, any help would be very much appreciated! Thanks!

System Info:

I have normal user in CentOS 7 whose name is "mostafa" (the name of the account).

I naturally have another user called root with all privileges. User "mostafa" is put into sudoers file, too.

The OS is installed in VmWare, so the system is all mine.

Problem:

Now I create a file with touch file.sh and put a command in it, but when I want to run it with Code:

sudo ./file.sh

, an error is shown that the command Code:

./file.sh

does not exist. But if I Code:

 sudo chmod 777 ./file.sh

then it gets run. My question is that, why should I use Code:

chmod 777

when I myself have created the file, and I am in sudoers.

Can anyone explain me why shuold I still use Code:

sudo chmod 777

when the creator of the file is me.

Hi All,
How can I replace the particular word using sed or awk
Code:

$ BUGZILLAURL="https://mylocalserver.com/bugzilla"
$ PROJECTNAME="mybugs"
$ echo "$BUGZILLAURL/$PROJECTNAME" 
https://mylocalserver.com/bugzilla/mybugs

There is a urlbase line in data/params file which has an empty variable, pls see 2nd line from below command's output.
Code:

$ grep -i "urlbase" data/params 
           'docs_urlbase' => 'docs/%lang%/html/',
           'urlbase' => '',
           'webdotbase' => 'http://www.research.att.com/~north/cgi-bin/webdot.cgi/%urlbase%',

Or search only for that line which I wanted to be as 'urlbase' => 'https://mylocalserver.com/bugzilla/mybugs',
Code:

$ grep -i "'urlbase'" data/params 
           'urlbase' => '',

So expecting your kind help to replace '' word with 'https://mylocalserver.com/bugzilla/mybugs' using sed or awk.

Thanks.