Visit Our UNIX and Linux User Community


sleep 10 && command doesn't work


 
Thread Tools Search this Thread
Top Forums UNIX for Dummies Questions & Answers sleep 10 && command doesn't work
# 1  
Old 03-12-2009
Question sleep 10 && command doesn't work

Hi there,
I found a trick to easily postpone a command by a few seconds:
Code:
supernova:~# sleep 10 && command &

If you logout, the command should still be executed... But not all the time.
Could anyone of you explain me why the following command is executed even after logging out:
Code:
supernova:~# sleep 10 && touch somefile &

and not that one:
Code:
supernova:~# sleep 10 && /etc/init.d/networking force-reload &

Thanks in advance
Santiago
# 2  
Old 04-15-2009
When you log out of a terminal, a HUP signal is sent to the shell, which passes that signal on to all the tasks/jobs you have running in that terminal. The && means "run the second command if the first command succeeded", and exiting with a signal usually means the command did [i]not[i] succeed, so the second command should not run. So the question really is, why does the first command work? That I am unsure about it. It could be a matter of timing -- you log out just as the sleep command exits.

If you are using BASH, there are several caveats to all this.

If you want to make sure something finishes even after you log off, you can do:
Code:
nohup sh -c "sleep 10; /etc/init.d/networking force-reload" &

# 3  
Old 04-21-2009
You're right otheus,
Actualy, when I run my touch command, if I logout immediatly (using ctrl+D) the windows freezes for 10 seconds before it actually closes. So obviously, it waits until the command complete and thus explains why the command indeed works.
Thanks for your idea!
 

Previous Thread | Next Thread
Test Your Knowledge in Computers #208
Difficulty: Medium
Open Shortest Path First (OSPF) was designed as an exterior gateway protocol (EGP) for use in an autonomous systems such as a local area network (LAN).
True or False?

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

SFTP Shell Script Get & Delete && Upload & Delete

Hi All, Do you have any sample script, - auto get file from SFTP remote server and delete file in remove server after downloaded. - only download specify filename - auto upload file from local to SFTP remote server and delete local folder file after uploaded - only upload specify filename ... (3 Replies)
Discussion started by: weesiong
3 Replies

2. Shell Programming and Scripting

If && command giving wrong output

Hi All, I am trying to run a script which will search for 2 strings(stopped,started) in a text file and echo an output depending on below condition -bash-3.2$ cat trial1.txt v ggg f -bash-3.2$ cat trial1.sh VAR9=` grep 'stopped' /tmp/trial1.txt` VAR10=` grep 'started'... (4 Replies)
Discussion started by: srkmish
4 Replies

3. Shell Programming and Scripting

Read input while another command is running &&

This script runs tshark, then displays the output. I want to read a keypress at all times throughout this script, especially during the 10 seconds that tshark is running. This code however, only takes input before tshark runs. #!/bin/bash main() { while (( "1" == "1" )) ; do keypress &&... (3 Replies)
Discussion started by: Kiah07
3 Replies

4. Shell Programming and Scripting

[Solved] BASH - chaining TEST and COMMAND with && and II

Can you explain what this line of script is doing. What I have understood is : -- variable C is the name of a software which is either not installed, so it must be installed or allready installed and then should be update if newer version found -- branch B="$B $C" is to install the software --... (4 Replies)
Discussion started by: jcdole
4 Replies

5. Shell Programming and Scripting

Replace & sign to &amp word

Hi, I have text file abc.txt. In this file, I have the following data. Input: Mr Smith &amp Mrs Smith Mr Smith &apos Mrs Smith Mr Smith & Mrs Smith Mr Smith& Mrs Smith Mr Smith &Mrs Smith Output: Mr Smith &amp Mrs Smith Mr Smith &apos Mrs Smith Mr Smith &amp Mrs Smith Mr Smith&amp... (4 Replies)
Discussion started by: naveed
4 Replies

6. Red Hat

/usr/bin/find && -exec /bin/rm never work as expected

hi there, Would you able to advise that why the syntax or statement below couldn't work as expected ? /usr/bin/find /backup -name "*tar*" -mtime +2 -exec /bin/rm -f {} \; 1> /dev/null 2>&1 In fact, I was initially located it as in crontab job, but it doesn't work at all. So, I was... (9 Replies)
Discussion started by: rauphelhunter
9 Replies

7. Shell Programming and Scripting

PHP read large string & split in multidimensional arrays & assign fieldnames & write into MYSQL

Hi, I hope the title does not scare people to look into this thread but it describes roughly what I'm trying to do. I need a solution in PHP. I'm a programming beginner, so it might be that the approach to solve this, might be easier to solve with an other approach of someone else, so if you... (0 Replies)
Discussion started by: lowmaster
0 Replies

8. HP-UX

sleep & localtime query

Hi, I work on HPUX application and i had a query regarding the sleep & localtime system call in HPUX. Here is the code that we have : const uint32_t WAKE_INTERVAL_SEC(30*60); while (true) { // Find out what time it is time(&currentTime);... (3 Replies)
Discussion started by: nsvora
3 Replies

9. UNIX for Dummies Questions & Answers

Problem with xterm & tcsh & sourcing a script in a single command

Hi friends, I have a script that sets the env variable path based on different conditions. Now the new path variable setting should not done in the same terminal or same shell. Only a new terminal or new shell should have the new path env variable set. I am able to do this only as follows: >cd... (1 Reply)
Discussion started by: sowmya005
1 Replies

10. UNIX for Advanced & Expert Users

Problem: Automounting Home directory for nis & nfs configuration doesn't work

Hi all, First of all, i am so sorry about my bad level in English writing. I have some problem in linux and i hope the experts of this forum to help me if they have enough time to reply to me. I have a scenario of configuring NIS and NFS in Redhat Linux environment such that user can login... (0 Replies)
Discussion started by: pioneer
0 Replies

Featured Tech Videos