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 CENTOS
wait_event_interruptible_exclusive_locked_irq
WAIT_EVENT_INTERRUPT(9) Driver Basics WAIT_EVENT_INTERRUPT(9)NAME
wait_event_interruptible_exclusive_locked_irq - sleep until a condition gets true
SYNOPSIS
wait_event_interruptible_exclusive_locked_irq(wq, condition);
ARGUMENTS
wq
the waitqueue to wait on
condition
a C expression for the event to wait for
DESCRIPTION
The process is put to sleep (TASK_INTERRUPTIBLE) until the condition evaluates to true or a signal is received. The condition is checked
each time the waitqueue wq is woken up.
It must be called with wq.lock being held. This spinlock is unlocked while sleeping but condition testing is done while lock is held and
when this macro exits the lock is held.
The lock is locked/unlocked using spin_lock_irq/spin_unlock_irq functions which must match the way they are locked/unlocked outside of this
macro.
The process is put on the wait queue with an WQ_FLAG_EXCLUSIVE flag set thus when other process waits process on the list if this process
is awaken further processes are not considered.
wake_up_locked has to be called after changing any variable that could change the result of the wait condition.
The function will return -ERESTARTSYS if it was interrupted by a signal and 0 if condition evaluated to true.
COPYRIGHT Kernel Hackers Manual 3.10 June 2014 WAIT_EVENT_INTERRUPT(9)