What Does | Bash -s Do? Any Example?

I need to compare a value with different fixed value. Below is the code concept I implemented in my bash script but its giving me error.
Here "a' is the nameserver value that I extract using command line from /etc/resolv.conf. I did not put command here.

#! /bin/bash
a=1.2.3.4

if [ $a == 1.2.3.4 || 5.6.7.8 || 8.9.1.4]
then
echo " You have correct ntpserver"
else
echo"wrong ntpserver"

fi

Am I comparing the value correctly or any suggestion?

Thank you

hi
I try to assign return from a _error_handler_function to a variable
this is just a test( dummy test ) not a really case


#!/bin/bash
logfile="/dev/shm/log.err"
exec 2>$logfile
_err_handler(){
v=$(cat $logfile|grep dummy|wc -l);
rm $logfile
echo $v
}

trap _err_handler ERR

x=$(dummy);
echo "x value is $x "
z=$(notrap)
echo "z value is $z"


expected output :
bash-4.1$ sh test2.sh
x value is 1
z value is 0


what is wrong here and how should I fix?

thanks in advance

I am looking to display the w (who) command to show only the

User TTY IDLE


http://screencast.com/t/vXb74kguJ

13:15:38 up 8 days, 16:48, 47 users, load average: 1.47, 0.95, 0.51
USER TTY FROM LOGIN@ IDLE JCPU PCPU WHAT
rf3 pts/0 192.168.11.72 05:58 48.00s 6.60s 0.00s -bash
user21 pts/1 192.168.21.177 04:32 8:41m 0.05s 0.00s -bash
user7 pts/2 192.168.11.114 17Mar15 6days 1.07s 0.00s -bash
user7 pts/3 192.168.11.114 20Mar15 4:54m 9.75s 0.00s -bash
user6 pts/4 192.168.11.85 11:02 7.00s 55.58s 0.01s -bash
user14 pts/5 192.168.11.183 05:06 29:08 2.80s 0.01s -bash
user14 pts/6 192.168.11.155 05:30 13:28 2.75s 0.00s -bash
user23 pts/7 192.168.11.62 05:48 25:09 0.95s 0.00s -bash
rf5 pts/8 192.168.11.118 05:58 6:51 5.30s 0.01s -bash
user2 pts/9 192.168.11.140 08:34 1:19 44.74s 0.00s -bash
user14 pts/10 192.168.11.141 06:02 12:14 9.46s 0.00s -bash
rf12 pts/12 192.168.11.69 06:02 2:07 9.44s 0.00s -bash
root pts/13 localhost.locald 12:29 9:10 0.05s 0.05s -bash
rf6 pts/14 192.168.11.79 06:04 14.00s 9.05s 0.00s -bash
user14 pts/15 192.168.21.113 06:23 11:29 1.71s 0.00s -bash
user5 pts/16 192.168.11.126 06:24 6:56 4.59s 0.00s -bash
user5 pts/17 192.168.11.126 06:25 6:19 31.59s 0.01s -bash
user11 pts/18 192.168.11.125 06:26 28:10 2.90s 0.01s -bash
user12 pts/19 192.168.21.123 06:35 13:16 0.88s 0.00s -bash
rf7 pts/20 192.168.11.80 06:35 2:06 7.64s 0.00s -bash
user12 pts/21 192.168.21.123 06:36 41:55 0.12s 0.00s -bash



So far I have this

w | awk {'printf ("6s\ts\n", $1, $2, $3, $5)'} |more
13:20:16 up
USER TTY
rf3 pts/0
user21 pts/1
user7 pts/2
user7 pts/3
user6 pts/4
user14 pts/5
user14 pts/6
user23 pts/7
rf5 pts/8
user2 pts/9
user14 pts/10
rf12 pts/12
root pts/13
This only shows the 2 columns



w |awk '{print $1, $2, $3, $5}'

13:21:01 up 8 16:53,
USER TTY FROM IDLE
rf3 pts/0 192.168.11.72 20.00s
user21 pts/1 192.168.21.177 8:46m
user7 pts/2 192.168.11.114 6days
user7 pts/3 192.168.11.114 4:59m
user6 pts/4 192.168.11.85 3:42
user14 pts/5 192.168.11.183 34:31
user14 pts/6 192.168.11.155 18:51
user23 pts/7 192.168.11.62 30:32
rf5 pts/8 192.168.11.118 12:14
user2 pts/9 192.168.11.140 1.00s
user14 pts/10 192.168.11.141 17:37
rf12 pts/12 192.168.11.69 30.00s
This shows some what hard to read and the columns don't line up correctly


is there a way to tab them in to columns that line up properly, or even something similar to the TOP command where the list will keep refreshing?

hi guys, im trying to understand the bash rules or hash tag rules.

my understanding is the the everything to the right of the bash command is not executed? is this right? and you disable it by using a new line to enter executable commands?

This is my script and the syntax to run this script is give ip and next will be the file or script you want to perform on remote server



#!/bin/bash

# The private key used to identify this machine
IDENTITY_KEY=/home/adnew.pem

syntax()
{
echo "Syntax: Ec2.sh server_ip scriptFile]"
echo "For example: ./Ec2.sh server_ip scriptFile"
exit 1
}

if [ $# -ne 2 ]
then
echo not enough arguments
syntax
fi


echo "Running script $2 on $1"
ssh -ttq -i $IDENTITY_KEY ec2-user@$1 sudo -i 'bash -s' < $2
exit
exit
echo "Done"



on script file i have give for testing

touch /root/test
ls /root/test
exit
exit

it makes the file but do not show the ls output by giving error


tcgetattr: Inappropriate ioctl for device

exit


what I have to do ??

Apologies. I've been out of Unix for 14 years, and the gears have rusted. Also, Unix has changed - enough similarities to memory that I'm pretty comfy though.

Glad to see lots of info available via google. However changes are going to take getting used to. Have set up a testbed of 3 nearly identical machines, hoping to make an (at home) private network where I can automate installs and set-ups using NIS and NFS (Similar to work I once did).

Have found useful scripts interspersed with comments, would like to copy and paste them to a bash script that:

Reads the line.
Echos the line.
Reads the reply.
Executes what is typed.

Essentially, by making myself type (or copy & paste) the commands I think I'll become familiar.

Figured I'd use a spreadsheet, select the file, and paste into column B of the spreadsheet. In column A I'd paste:

echo "

and in column C I'd paste:

"

Then I'd cut and paste into a text document, insert the lines:

read A
$A

behind every command necessary to the actual task.

Figured I'd have to escape the ' and ".

Ran a test (test.bash):

#!/bin/bash
for i in `seq 1 10`;
do
echo "Enter a command:"
read A
echo "Trying $A"
$A
done

works fine when I type

ls -alg

but not so when I type

ls -alg | grep dwrx

so I'm wondering if someone has a suggestion?

Thanks for any ideas.

When I run the .cmd file in the cluster I am getting an error message as

/bin/bash: : No such file or directory

The below is the PBS script in the .cmd file

#! /bin/bash
#PBS -o logfile.log
#PBS -e errorfile.err
#PBS -l cput=740:00:00
#PBS -l select=2:ncpus=8
tpdir=`echo $PBS_JOBID | cut -f 1 -d .`
tempdir=$HOME/work/job$tpdir
mkdir -p $tempdir
cd $tempdir
cp -R $PBS_O_WORKDIR/* .
fluent 2ddp -g -t16 -pib -cnf=$PBS_NODEFILE -ssh -i srik.jou >> out
mv ../job$tpdir $PBS_O_WORKDIR/.

Please help me to figure out the problem.

Hi Everyone,

I need some help on my bash script, I'm trying to rename a certain line in a file which might be 1 or more.

IDXCOUNT=`grep -c 'index .* on ' $FILENAME`;

for n in $(eval echo {1..$IDXCOUNT});
do
timestamp=$(date +"%s");
echo "Renaming index idx_$timestamp..";
if [ $n -eq 1 ]; then
sed -i "0,/^index [^)]* on /s/index idx_$timestamp on /" $FILENAME;

My problem is, if the sed target is 2 or more it will generate an idx_$timestamp that will cause duplicate index value when the script finish. My goal is to have the script recognize that when there are multiple index in the file, it will try to rename it one by one.

I'm new to bash so I'm not sure if I explained my issue well but I will appreciate any help!!

Thanks!

I am have a bash script like this:

#!/bin/bash
while true;
do
(printf %s "$(date '+%A %W %Y %X')"; echo -n ", " ; printf %s "$(ps -eo pcpu,pmem,comm | grep statsd)") >> tope.txt;
sleep 2;
done

What I want is the output of this command be entered into tope.txt like this:

Friday 20 2015 11:28:21, 0.0 0.4 /usr/libexec/systemstatsd

but what I get is output like this in multiline. :

Friday 20 2015 11:28:21
,
0.0 0.4 /usr/libexec/systemstatsd

What can I do to fix this?

I have a bash script executing on an AIX server to a windows share directory to update a windows text file. Most of the file is edited as expected but I have 3 issues that I am not sure how to resolve.

1. Windows text file contains a double backslash (\\) and the \\ is being written back as a single \ which corrupts the file.
2. I am not getting the last line of text in the file written back out.
3. Some lines of text are not written back out completely.

Here is a snippet of my bash script:
cp $Directory/Somefile $Directory/Somefile.$(date +'%Y%m%d')
cat /dev/null > ${HOME}/temp.out

while read -r inpLine; do
patternFound=n
echo ${inpLine} | grep -q 'SOMEPATTERN='
if [ $? = 0 ]; then
patternFound=y
echo "##${inpLine}" >> ${HOME}/temp.out
echo "SOMEPATTERN=newValue" >> ${HOME}/temp.out
fi

if [ ${patternFound} = "n" ]; then
echo ${inpLine} >> ${HOME}/temp.out
fi

done < $Directory/Somefile
mv ${HOME}/temp.out $Directory/Somefile