The braces are used when there are multiple commands you want to execute after || but you could also write this as an "if then else" if that's more convenient. Then it's easier to add commands, too.
The braces and the semicolons are not necessary here, because everything up to "fi" (or "else") is executed when the condition matches. The || { stuff; } syntax is just basically a shorthand for when you want to cram stuff into a one-liner.
Hi friends, :)
In a shell script i found the following if condition.
echo -n "Which version of $1 do you want to restore ('0' to quit)? : "
read desired
if ${desired:=1} -ge $index ] ; then
echo "$0: Restore canceled by user: index value too big." >&2
exit 1
fi
Can... (1 Reply)
i have a paramter data_date in which i am passing a string value.i want to find out another paramter file_date from this.the logic is given below
if day of data_date = sunday or monday
then
file_date=data_date-1
else
file_date=data_date-2
i am passing data_date as 20061027.
how can i... (3 Replies)
Hi,
I am trying to execute this command, but is it not working, says "`;' unexpected"
eval $lgrep $SAM_CMD ; if ; then ; echo "No Error" ; fi
What i want is, return the command output, if it is non zero, say "No Error".
Thanks, John. (21 Replies)
Executed the following if conditions .. and got different results .
only (( )) gave correct o/p with all scenarios .
Can anybody please let me know what is the difference between and ] and ((condition)) when used with if condition.
And why each condition gave different result.
1.... (2 Replies)
hi,
I have some problems in my simple script about the redirect echo stdout command inside a condition. Why is the echo command inside the elif still execute in the else command
Here are my simple script
After check on the two diff output the echo stdout redirect is present in two diff... (3 Replies)
HI
My doubt may be basic one but I need to get it clarified..
When i use "if" condition that checks for many AND, OR logical conditions
like
if ]; then
return 0
fi
Even the if condition fails it returns as zero.. Any clue..
But if i add else condition like
if ]; ... (2 Replies)
Hi all
Unix newbie - please be gentle
Am modifying an existing script to error trap a variable with a length of 0
#!/bin/bash
ipfile='/var/data/bin/ipaddress'
] && ipold="$(< "$ipfile" )"
ipnew="$( wget -q -O - checkip.dyndns.org | sed -e 's/.*Current IP Address: //;s/<.*$//' )"
#... (6 Replies)
o/p of my command is given below
My requirement is
if Pnumber is 0 then
stabilization.Build.2013
else
stabilization.PBuild.2013.3 (11 Replies)
Discussion started by: nikhil jain
11 Replies
LEARN ABOUT HPUX
pthread_cond_broadcast
pthread_cond_signal(3T)pthread_cond_signal(3T)NAME
pthread_cond_signal(), pthread_cond_broadcast() - unblock one or all threads waiting on a condition variable
SYNOPSIS PARAMETERS
cond Pointer to the condition variable to be signaled or broadcast.
DESCRIPTION
The function is used to wake-up one of the threads that are waiting for the occurrence of a condition associated with condition variable
cond. If there are no threads blocked on cond, this function has no effect. If more than one thread is blocked on cond, the scheduling
policy determines which thread is unblocked. It is possible that more than one thread can be unblocked due to a spurious wakeup.
The function is used to wake-up all threads that are waiting for the occurrence of a condition associated with the condition variable cond.
If there are no threads blocked on cond, this function has no effect. If more than one thread is blocked on cond, the scheduling policy
determines the order in which threads are unblocked.
The condition variabled denoted by cond must have been dynamically initialized by a call to or statically initialized with the macro
An unblocked thread will reacquire the mutex it held when it started the condition wait before returning from or The threads that are
unblocked contend for the mutex according to their scheduling policy and priority.
The or functions can be called by a thread whether or not it currently owns the condition variable's associated mutex. For predictable
scheduling behavior and to prevent lost wake-ups, the mutex should be held when signaling a condition variable.
Usage
When using condition variables, there is a boolean predicate associated with each condition wait. If this predicate is false, the thread
should do a condition wait. Spurious wakeups may occur when waiting on a condition variable. Because the return values from and do not
imply anything about the value of this predicate, the predicate should always be re-evaluated.
Applications using condition variables typically acquire a mutex and enter a loop which checks the predicate. Depending on the value of
the predicate, the thread either breaks out of the loop or waits on the condition. On return from the condition wait, the predicate is re-
evaluated.
RETURN VALUE
Upon successful completion, and return zero. Otherwise, an error number is returned to indicate the error (the variable is not set).
ERRORS
For each of the following conditions, if the condition is detected, the and functions return the corresponding error number:
[EINVAL] cond is not a valid condition variable.
[EFAULT] cond parameter points to an illegal address.
AUTHOR
and were derived from the IEEE POSIX P1003.1c standard.
SEE ALSO pthread_cond_init(3T), pthread_cond_wait(3T).
STANDARDS CONFORMANCE
Pthread Library pthread_cond_signal(3T)