command to redirect output to console and to a file at the same time works fine in bash. But how do i make it work in korn shell(ksh).
All my scripts runs on korn shell so cant change them to bash for this particular command to work.
exec > >(tee -a $LOGFILE) 2>&1
In the code beneath I use the variable logfile, lowercase is better.
You can try something like
touch "${logfile}"
tail -f "${logfile}"&
tailpid=$!
trap 'kill -9 ${tailpid}' EXIT INT TERM
exec 1>"${logfile}" 2>&1
A not too unreasonable technique is to re-exec the shell with output to tee. That is, at the top of the script, do something like:
#!/bin/sh
test -z "$REXEC" && { REXEC=1 exec "$0" "$#" | tee -a $LOGFILE; exit; }
Nohup redirects stderr to stdout if it points to a terminal. But I want to retain stderr output to the terminal
Is there a way to accomplish that? Is there an alternative?
I don't know if I understood correctly or not.
you mean that you don't want to see the error in terminal?
if yes:
if you want to save the error in file:
nohup command 2> file.txt
if you don't need the errors:
nohup command 2> /dev/null
2 means the error output of command
2> file.txt means write the error output to the file.txt
Just redirect it somewhere else, so it's not the terminal:
nohup bash -c 'echo OUT ; echo ERR >& 2' 2> err
You can redirect the stderr back to stdout instead of to a file to keep the output in the terminal, but it doesn't make much sense: nohup is for situations where the terminal might get lost, in which case you'll lose the stderr.
nohup bash -c 'echo OUT ; echo ERR >& 2' 2> >(cat)
Here is my script (run.sh):
rm -f nohup.out
nohup myproc &
tailf nohup.out
If I run the script (sh run.sh) then press Control-C, myproc will be terminated,
but if I comment the tailf nohup.out part, myproc will run on background as expected.
Am I doing anything wrong?
The problem is not SIGHUP (which nohup would catch) but SIGINT which you send by pressing Control-C. This is propagated to your process.
See this blog post for more details.
From what I read from that post you could change your code to something like this:
setsid myproc 1> output.log 2>&1 &
tail -f output.log
If you dont want to use your own output redirection, you can still use nohup:
setsid nohup ping -c 30 localhost &
tail -f nohup.out
Hope this helps!
Is there a way to redirect the nohup output to the stdin instead of nohup.out ?
I've tried:
nohup echo Hello > /dev/stdin 2>&1 &
But it does not the trick.
The nohup command purposefully detaches itself from the stdin, so there is nothing it expects to read in itself, and thus I think what you are really after in this question, is redirecting the output of nohup as the stdin for the next command. (Well somebody has to read the stdin, and it ain't nohup.)
Further, POSIX mandates that the output goes to the nohup.out file in the working directory, if the file can be successfully opened. So what you can do is to wire the stdin of the following commands from the nohup.out file. For instance:
$ nohup echo Hello 2>/dev/null; read VAR 0<nohup.out; echo "VAR=$VAR"
VAR=Hello
Linux newbie here.
I have a perl script which takes two command line inputs. I tried to run it in the background but this is what I got:
[~user]$ nohup sudo ./ascii_loader_script.pl 20070502 ctm_20070502.csv &
[2] 19603
[~user]$ nohup: appending output to `nohup.out'
after the system returns "nohup: appending output to `nohup.out'", no new prompt will appear. Then as long as I type in some other command, the shell will tell me that the process is stopped:
[~user]$ nohup sudo ./ascii_loader_script.pl 20070502 ctm_20070502.csv &
[2] 19603
[~user]$ nohup: appending output to `nohup.out'
ls
ascii_loader_script.pl format_wrds_trd.txt nohup.out norm_wrds_trd.cfg
[2]+ Stopped nohup sudo ./ascii_loader_script.pl 20070502 ctm_20070502.csv
I've looked at this post and tried to do "sudo date" before executing the command. Still got the same thing.
http://www.sudo.ws/pipermail/sudo-users/2003-July/001648.html
The solution is to use the -b flag for sudo to run the command in the background:
$ sudo -b ./ascii_loader_script.pl 20070502 ctm_20070502.csv
You should only use nohup if you want the program to continue even after you close your current terminal session
The problem here, imho, is not nohup, but background processing sudo.
You are putting the process in background (& at end of command) but probably sudo needs password authentication, and that is why the process stops.
Try one of these:
1) remove the ampersand from end of command, reply to passord prompt and afterwords put it in background (by typing CTRL-Z - which stops the process and issuing the bg command to send it to background)
2) Change the /etc/sudoers to not ask for users password by including the line:
myusername ALL=(ALL) NOPASSWD: ALL
If besides the password reply your application waits for other input, then you can pipe the input to the command like this:
$ cat responses.txt|sudo mycommand.php
hth
You can Try
sudo su
and then
nohup ./ascii_loader_script.pl 20070502 ctm_20070502.csv &
instead of
nohup sudo ./ascii_loader_script.pl 20070502 ctm_20070502.csv &
You must use sudo first, nohup second.
sudo nohup ./ascii_loader_script.pl 20070502 ctm_20070502.csv &
My working solution for evaluating disk fragmentation in the background:
Exec sudo with nohup without ampersand (&) at the end:
$ sudo nohup nice -20 find / -type f -exec filefrag "{}" \; | sed 's/^\(.*\): \([0-9]\+\) extent.*/\2\t\1/'| awk -F ' ' '$1 > 0' | sort -n -r | head -50 > filefrag.txt
Enter password for sudo;
Press Ctrl+Z;
Put the running process in the background.
$ bg 1
[1]+ sudo nohup nice -20 find / -type f -exec filefrag "{}" \; | sed 's/^\(.*\): \([0-9]\+\) extent.*/\2\t\1/' | awk -F ' ' '$1 > 0' | sort -n -r | head -50 > filefrag.txt &
Now you can exit the terminal and log in later. The process will remain running in the background. Because nohup is used.
First of all, you should switch sudo and nohup.
And then:
if sudo echo Starting ...
then
sudo nohup <yourProcess> &
fi
The echo Starting ... can be replaced by any command that does not do much.
I only use it as dummy command for the sudo.
By this the sudo in the if-condition triggers the password-check.
If it is ok then the sudo session is logged in and the second call will succeed, otherwise the if will fail and not execute the actual command.
I open an editor and typed these lines:
#!/bin/bash
sudo echo Starting ...
sudo -b MyProcess
(Where MyProcess is anything I want to run as superuser.)
Then I save the file where I want it as MyShellScript.sh .
Then change the file permissions to allow execution.
Then run it in a terminal. the "-b" option tells sudo to run the process separately in the background, so the process keeps running after the terminal session dies.
Worked for me in linux-mint.
You can set it as your alias:
sudo sh -c 'nohup openvpn /etc/openvpn/client.ovpn 2>&1 > /dev/null &'
This should work
sudo -b -u userName ./myScript > logFile
I am just curious to understand that can I send this logFile as a email after the ./myScript is successful running in background.
Try:
xterm -e "sudo -b nohup php -S localhost:80 -t /media/malcolm/Workspace/sites &>/dev/null"
When you close xterm, the PHP web server still alive.
Don't put nohup before sudo or else the PHP web server will be killed after closing xterm.