It makes no sense to put a background statement in backticks, is the problem.
Yes indeed absolutely right.
I've spent some more time on this today and have some code as a proof of concept (I know it needs error checking added) but can you guys spot any problems/errors/bad practice with the following working code?
It has no sleep required, accepts timeouts with fractions of a second, and seems to do the job.
One problem though, the "kill -9" statement always ends up outputting a line like this (below) in the shell even with the re-direct, where am I going wrong with that?
Code:
./test: line 56: 5968 Killed $urlDownloaderProg "$url" > $tempFileName
Code:
#!/bin/bash
# Usually responds fast ( < 200 ms)
url="http://checkip.dyndns.org"
# Usually responds slow ( > 1000 ms)
# url="http://www.dnsstuff.com/"
urlDownloaderProg="curl --silent"
tempFileName=$(mktemp --quiet "temp.XXXXXX")
$urlDownloaderProg "$url" > $tempFileName &
pid=$!
timeoutStart=$(date +%s.%N)
timeout="1.0"
finished="No"
processFinished="No"
while [ "$finished" = "No" ]; do
ps -e | grep --quiet "$pid"
grepRetVal=$?
if [ "$grepRetVal" -ne "0" ]; then
finished="Yes"
processFinished="Yes"
fi
timeoutNow=$(date +%s.%N)
bcExp="if ($timeoutNow - $timeoutStart > $timeout) { print 1 } else { print 0 }"
bcRes=$(echo "$bcExp" | bc -l)
if [ "$bcRes" -eq "1" ]; then
finished="Yes"
fi
done
if [ "$processFinished" = "Yes" ]; then
tempFileContents=$(cat $tempFileName)
grepExpr="[0-9]+\.[0-9]+\.[0-9]+\.[0-9]+"
ipAdd=$(echo "$tempFileContents" | grep -Eo "$grepExpr" | uniq)
echo $ipAdd
else
kill -9 "$pid" > /dev/null 2>&1
fi
if [ -f "$tempFileName" ]; then rm "$tempFileName"; fi
I have a command which will run fine in a unix command prompt. Can you tell how to interprete this command inside perl script......
The command is :
perl -pe 's/(\|333\}.*)\}$/$1|1.6}/' FIA.txt
This will search for the number 333 and appends 1.6 at the end of that line....... (1 Reply)
I'm new to Linux. I have a bash script that invokes an executable. I'd like use the SCRIPT command inside the script and exit out of the script command after it writes to the file. Does this make sense? Below is an example of the contents of my script.
#BEGIN SCRIPT
script typescript... (6 Replies)
Hi everyone,
when executing this command in unix:
echo "WM7 Fatal Alerts:", $(cat query1.txt) > a.csvIt works fine, but running this command in a shell script gives an error saying that there's a syntax error.
here is content of my script:
tdbsrvr$ vi hc.sh
"hc.sh" 22 lines, 509... (4 Replies)
Hi All,
Is there any way to monitor a command inside shell script ? I have a script inside which I have a tar command which zips around 200GB data.
tar zcvf $Bckp_Dir/$Box-BaseBackup-$Day.tar.gz * --exclude 'dbserver_logs/*' --exclude postmaster.pid --exclude 'pg_xlog/*'
I want to... (3 Replies)
Hi,
I have a script file in server A. Inside the script file, I first have a ssh command that will connect to a remote server B. In the same script file itself, I have a sequence of commands that has to be run in server B. I am embedding these commands in the script file that I have in server A.... (2 Replies)
hii,,
I am trying to automate jira. during my scripting using bash script, in the terminal i got the terminal message like this:
"Configure which ports JIRA will use.
JIRA requires two TCP ports that are not being used by any other
applications on this machine. The HTTP port is where you... (1 Reply)
Hi ,
DIR1 has only one file with .txt extension , trying to get the size of that file using the following script
#!/bin/ksh
foldr_1="/etc/DIR1"
#echo "$foldr_1"
sze_fdr1=$(ls -ltr foldr_1/*.txt |awk '{ print $5 }')
echo "$sze_fdr1"
After executing the above script getting... (1 Reply)
hi,
how can i know whether a command inside an sftp script has failed or not?
i have a sftp expect script
#!/usr/bin/expect
spawn /usr/bin/sftp abc@ftp.abc.com
expect "sftp>"
send "cd dir\r"
expect "sftp>"
send "mput abc.txt\r"
expect "sftp>"
send "mput def.xls\r"
expect "sftp>"... (5 Replies)
My script needs to take a folder path to the location of a C program, and run the program until the user selects exit in his C program. The script needs to create a transcript to a text file while the C program is running.
Creating a transcript can be easily done with the script command but it... (2 Replies)
Discussion started by: syntax_eror
2 Replies
LEARN ABOUT X11R4
wait
wait(1) User Commands wait(1)NAME
wait - await process completion
SYNOPSIS
/bin/sh
wait [pid...]
/bin/jsh /bin/ksh /usr/xpg4/bin/sh
wait [pid...]
wait [ % jobid...]
/bin/csh
wait
DESCRIPTION
The shell itself executes wait, without creating a new process. If you get the error message cannot fork,too many processes, try using the
wait command to clean up your background processes. If this doesn't help, the system process table is probably full or you have too many
active foreground processes. There is a limit to the number of process IDs associated with your login, and to the number the system can
keep track of.
Not all the processes of a pipeline with three or more stages are children of the shell, and thus cannot be waited for.
/bin/sh, /bin/jsh
Wait for your background process whose process ID is pid and report its termination status. If pid is omitted, all your shell's currently
active background processes are waited for and the return code will be 0. The wait utility accepts a job identifier, when Job Control is
enabled (jsh), and the argument, jobid, is preceded by a percent sign (%).
If pid is not an active process ID, the wait utility will return immediately and the return code will be 0.
csh
Wait for your background processes.
ksh
When an asynchronous list is started by the shell, the process ID of the last command in each element of the asynchronous list becomes
known in the current shell execution environment.
If the wait utility is invoked with no operands, it will wait until all process IDs known to the invoking shell have terminated and exit
with an exit status of 0.
If one or more pid or jobid operands are specified that represent known process IDs (or jobids), the wait utility will wait until all of
them have terminated. If one or more pid or jobid operands are specified that represent unknown process IDs (or jobids), wait will treat
them as if they were known process IDs (or jobids) that exited with exit status 127. The exit status returned by the wait utility will be
the exit status of the process requested by the last pid or jobid operand.
The known process IDs are applicable only for invocations of wait in the current shell execution environment.
OPERANDS
The following operands are supported:
One of the following:
pid The unsigned decimal integer process ID of a command, for which the utility is to wait for the termination.
jobid A job control job ID that identifies a background process group to be waited for. The job control job ID notation is applicable
only for invocations of wait in the current shell execution environment, and only on systems supporting the job control option.
USAGE
On most implementations, wait is a shell built-in. If it is called in a subshell or separate utility execution environment, such as one of
the following,
(wait)
nohup wait ...
find . -exec wait ... ;
it will return immediately because there will be no known process IDs to wait for in those environments.
EXAMPLES
Example 1: Using A Script To Identify The Termination Signal
Although the exact value used when a process is terminated by a signal is unspecified, if it is known that a signal terminated a process, a
script can still reliably figure out which signal is using kill, as shown by the following (/bin/ksh and /usr/xpg4/bin/sh):
sleep 1000&
pid=$!
kill -kill $pid
wait $pid
echo $pid was terminated by a SIG$(kill -l $(($?-128))) signal.
Example 2: Returning The Exit Status Of A Process
If the following sequence of commands is run in less than 31 seconds (/bin/ksh and /usr/xpg4/bin/sh):
sleep 257 | sleep 31 &
jobs -l %%
then either of the following commands will return the exit status of the second sleep in the pipeline:
wait <pid of sleep 31>
wait %%
ENVIRONMENT VARIABLES
See environ(5) for descriptions of the following environment variables that affect the execution of wait: LANG, LC_ALL, LC_CTYPE, LC_MES-
SAGES, and NLSPATH.
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
|Interface Stability |Standard |
+-----------------------------+-----------------------------+
SEE ALSO csh(1), jobs(1), ksh(1), sh(1), attributes(5), environ(5), standards(5)SunOS 5.10 12 Dec 1997 wait(1)