Hi All,
Good morning
I have a below code which is working & getting expected output. the problem in this code is it is executing 3 if conditions, my requirement is
suppose if first condition is success then it should print echo statement & exit from if condition
else if the 1st if condition got failed then it should goto next 2nd if condition and executes cmds... here if its success then it should print echo statement & exit from if condition
else if the 2nd if condition got failed then it should goto next 3rd if condition and executes cmds... here if its success then it should print echo statement & exit from if condition else print echo statements given in code
I have tried using case but its not generating expetected results
the output stored in variable may contain either any one of the below:
1> access Denied for server
2> access for apache is successfull
3> couldn't access the server
if the above three are not stored in a variable then it prints a msg "unknown error"
Hi,
Can any one pelase tell me how to grep multiple strings from multiple files in a singel folder?
grep -E "string1|string2|string3|string4|string..."
its taking lots of time..
can any please tell me fast grep???
URGENT (10 Replies)
Hello All,
I have a big file about 1000 lines. Now i am trying to grep a particular string and printing the lines from the string.
say for example in 500th line i have the date as "Mon Wed 14 20:15:24 2010". now i in my case i need to grep the combination of the strings "Mon Wed 14" and the... (7 Replies)
I have a script that periodically checks the Apache error_log to search for a specific error that causes it to hand and, if found, it restarts the service.
I recently found another error that forces it to hand and won't serve pages until it is reset. What I'm trying to do is to get the script to... (3 Replies)
Hello,
Here I have some grep command which is not working correctly:
cat file1.txt:
apples
Date: Sun, 24 Feb 2013 8:14:06 -0800
peaches melons
cherry sky cloud
green purple
yellow
cat file2.txt:
apples
Date
peaches melons 0800
cherry sky cloud
green purple
black (2 Replies)
I have this code
TrackingId:1362412470675;MSISDN:; INFO - number of clietns:3:Received response is: EMSResponse , protocolVersion=5, purchaseOptions=null, serviceData=ServiceData , screenData=CanvasData ]], title=null, titleResource=MessageResource], screenType=null]], serviceId=idBamboo,... (7 Replies)
Hi I have the server.log file as:
Server Stopped
ABC
DEF
GHI
JKL
Server Started
MNO
PQR
STU
Server Stopped
VWX
YZ
ABC
Server Started
Server Stopped
123
456
789 (9 Replies)
Hi,
I am trying to get the PID of a process that is defunct. I have two quesitons on this.
1) how do I pass in two strings? This is what I am using now:
ps -ef |egrep -i "programname|<defunct>"
But this returns multiple results with the word defunct in them.
2) How do I make it so that... (1 Reply)
Hi,
Mozilla/5.0 (Macintosh; Intel Mac OS X 10_10_2) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.94 Safari/537.36
How can I grep for the strings chrome and safari from a file, and if chrome print Chrome/40.0.2214.94 to a file and also count the number of times chrome is found?
... (4 Replies)
Discussion started by: cyberfrog
4 Replies
LEARN ABOUT PLAN9
flock
FLOCK(1) User Commands FLOCK(1)NAME
flock - manage locks from shell scripts
SYNOPSIS
flock [options] file|directory command [arguments]
flock [options] file|directory -c command
flock [options] number
DESCRIPTION
This utility manages flock(2) locks from within shell scripts or from the command line.
The first and second of the above forms wrap the lock around the execution of a command, in a manner similar to su(1) or newgrp(1). They
lock 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 an open file by its file descriptor number. See the examples below for how that can be used.
OPTIONS -c, --command command
Pass a single command, without arguments, to the shell with -c.
-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.
-F, --no-fork
Do not fork before executing command. Upon execution the flock process is replaced by command which continues to hold the lock.
This option is incompatible with --close as there would otherwise be nothing left to hold the lock.
-e, -x, --exclusive
Obtain an exclusive lock, sometimes called a write lock. This is the default.
-n, --nb, --nonblock
Fail rather than wait if the lock cannot be immediately acquired. 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.
-s, --shared
Obtain a shared lock, sometimes called a read lock.
-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.
-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. The zero number of seconds is interpreted as --nonblock.
--verbose
Report how long it took to acquire the lock, or why the lock could not be obtained.
-V, --version
Display version information and exit.
-h, --help
Display help text 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, except when using either of the options -n or -w which report a failure to
acquire the lock with a return value given by the -E option, or 1 by default.
When using the command variant, and executing the child worked, then the exit status is that of the child command.
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 <https://www.kernel.org/pub/linux/utils
/util-linux/>.
util-linux July 2014 FLOCK(1)