Hi,
I have a script to FTP the files to other unit.
Manually this script is running fine & files are getting transferred.
But running the same script using crontab does not transfer files, although the cron log shows that the file was executed.
PLz suggest (2 Replies)
Hi all,
i'm a newbie here, I'm just wondering how can i call my second script if it's contain successfull.
script1.sh
how can i call my 2nd script if he contain SUCCESSFULL
script2.sh
SUCCESSFULL
please advise,
Thanks, (10 Replies)
Hi All,
Requirement: The below script should automatically exit at 6pm everyday without manually killing the script
Tried running with the below shell script but found the script was still running when the time was 6:15pm. The script did not exit the while loop at 6pm
The script runs... (6 Replies)
Hi ,
Please excuse me for opening a new thread i am unable to find out the syntax error
in my if else condition inside for loop in awk command ,
my actual aim is to print formatted html td tag when if condition (True) having string as "failed",
could anyone please advise what is the right... (2 Replies)
Hi, I have written a script that allows me to repetitively play a music file $N times, which is specified through user input. However, if I want to exit the script before it has finished looping $N times, if I use CTRL+c, I have to CTRL+c however many times are left in order to complete the loop.... (9 Replies)
Hi,
I have first script which on IR remote command event execute the second script. If the second script is executed, it display echo "timeout expired" after 10s. This works as expected.
But I also want to reset timer (increase time) in case if the second script is executed again within 10s.
... (8 Replies)
I am trying to check multiple server's "uptime" in a loop over "ssh".
When I execute multiple ssh commands with hard coded servernames script is executing fine.
But when I pass server names using while loop, script is exiting after checking first server's status, why?
# serverList... (8 Replies)
Hi,
I am writing a menu driven program using shell script. THe script will be collecting data by logging into the other servers and bringing back the data to home server to process it and accordingly issue commands. TO automate commands execution , I am using expect script. However I am not able... (5 Replies)
Morning all,
I am attempting to complete the below script which will do the following (skip the ping part) using Bash.
Prompts the user to type in a URL to download, or to type exit to exit the script.
If a URL is typed, wget to download the webpage and then loop back to prompting for a... (2 Replies)
Discussion started by: Jgerds1990
2 Replies
LEARN ABOUT CENTOS
flock
FLOCK(1) User Commands FLOCK(1)NAME
flock - manage locks from shell scripts
SYNOPSIS
flock [options] <file|directory> <command> [command args]
flock [options] <file|directory> -c <command>
flock [options] <file descriptor number>
DESCRIPTION
This utility manages flock(2) locks from within shell scripts or the command line.
The first and second forms wrap the lock around the executing a command, in a manner similar to su(1) or newgrp(1). It locks a specified
file or directory, which is created (assuming appropriate permissions), if it does not already exist. By default, if the lock cannot be
immediately acquired, flock waits until the lock is available.
The third form uses open file by file descriptor number. See examples how that can be used.
OPTIONS -s, --shared
Obtain a shared lock, sometimes called a read lock.
-x, -e, --exclusive
Obtain an exclusive lock, sometimes called a write lock. This is the default.
-u, --unlock
Drop a lock. This is usually not required, since a lock is automatically dropped when the file is closed. However, it may be
required in special cases, for example if the enclosed command group may have forked a background process which should not be hold-
ing the lock.
-n, --nb, --nonblock
Fail rather than wait if the lock cannot be immediately acquired. See the -E option for the exit code used.
-w, --wait, --timeout seconds
Fail if the lock cannot be acquired within seconds. Decimal fractional values are allowed. See the -E option for the exit code
used.
-o, --close
Close the file descriptor on which the lock is held before executing command . This is useful if command spawns a child process
which should not be holding the lock.
-E, --conflict-exit-code number
The exit code used when the -n option is in use, and the conflicting lock exists, or the -w option is in use, and the timeout is
reached. The default value is 1.
-c, --command command
Pass a single command, without arguments, to the shell with -c.
-h, --help
Print a help message.
-V, --version
Show version number and exit.
EXAMPLES
shell1> flock /tmp -c cat
shell2> flock -w .007 /tmp -c echo; /bin/echo $?
Set exclusive lock to directory /tmp and the second command will fail.
shell1> flock -s /tmp -c cat
shell2> flock -s -w .007 /tmp -c echo; /bin/echo $?
Set shared lock to directory /tmp and the second command will not fail. Notice that attempting to get exclusive lock with second
command would fail.
shell> flock -x local-lock-file echo 'a b c'
Grab the exclusive lock "local-lock-file" before running echo with 'a b c'.
(
flock -n 9 || exit 1
# ... commands executed under lock ...
) 9>/var/lock/mylockfile
The form is convenient inside shell scripts. The mode used to open the file doesn't matter to flock; using > or >> allows the lock-
file to be created if it does not already exist, however, write permission is required. Using < requires that the file already
exists but only read permission is required.
[ "${FLOCKER}" != "$0" ] && exec env FLOCKER="$0" flock -en "$0" "$0" "$@" || :
This is useful boilerplate code for shell scripts. Put it at the top of the shell script you want to lock and it'll automatically
lock itself on the first run. If the env var $FLOCKER is not set to the shell script that is being run, then execute flock and grab
an exclusive non-blocking lock (using the script itself as the lock file) before re-execing itself with the right arguments. It
also sets the FLOCKER env var to the right value so it doesn't run again.
EXIT STATUS
The command uses sysexits.h return values for everything else but an options -n or -w failures which return either the value given by the
-E option, or 1 by default.
AUTHOR
H. Peter Anvin <hpa@zytor.com>
COPYRIGHT
Copyright (C) 2003-2006 H. Peter Anvin.
This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICU-
LAR PURPOSE.
SEE ALSO flock(2)AVAILABILITY
The flock command is part of the util-linux package and is available from Linux Kernel Archive <ftp://ftp.kernel.org/pub/linux/utils/util-
linux/>.
util-linux September 2011 FLOCK(1)