hi all. i have a little problem. im basically reading input from the user from the keyboard into the variable "phonenumber". I want to do a little error check to check if the user doesnt enter anything in for the value phonenumber.
i had this:
read phonenumber
if
then
.....
else
........ (2 Replies)
Hey all. Thanks in advance for any help you can give, hopefully this is an easy one. I want to create a loop to run a simple performance monitor like vmstat and record it to a file, but have very limited scripting skills (obviously).
Starting with this...
date >> /var/log/perfmon.log
vmstat... (2 Replies)
I'm just trying to make a script that runs in command line to echo each line in a text file. Everything i found on google is telling me to do it like this but when I run it it just echos removethese.txt and thats it. Anyone know what im doing wrong?
for i in removethese.txt; do echo $i; done
... (4 Replies)
Hi everyone - I am sure this is a really simple problem but I'm a total noob at Linux scripting:
I wanted to create a script that allows me to compare the current week number to the contents of a text file in my home directory:
VAR1='date +%V'
VAR2='cat /home/fred/file.txt'
... (6 Replies)
Hi everyone, I am facing to one shell script problem, which is as following
Write a shell script that:
Takes a number of arguments.
For each argument, print out all files in the current directory that contain this substring in their name.
I know I need to use grep for the second... (7 Replies)
I am trying to create a simple ksh loop script. What I've pasted below is not working. Any help is appreciated.
typeset -i count
typeset -i tcount
count=0
tcount=0
while $tcount >= 11
do
print "\$count is $count"
pwd
ls -l
sleep 30
$(( $tcount = $count + 1 ))
... (5 Replies)
Hi,
I am completely new to shell scripting. Basically I am wanting to create a simple while loop script to check if a network connection is available from 'netstat -a' and if its present then output a character to the serial port. I think i am nearly there.. but need some assistance.. this is... (9 Replies)
Hi all,
Please guide me writing this script
Follwing is the file which I have created, which contains the files to be copied.
cat system1-dr.txt
/etc/passwd
/etc/shadow
/etc/group
/etc/vfstab
/etc/profile
/etc/default/init
/etc/shells
/etc/dfs/dfstab
/etc/dfs/sharetab... (11 Replies)
Dear unix wizards,
I'd be very grateful for your help with the following.
I have a hypothetical file (file.txt) with three columns:
111 4 0.01
112 3 0.02
113 2 0.03
114 1 0.04
115 1 0.06
116 2 0.02
117 3 0.01
118 4 0.05
Column 2 consists of pairs of integers from 1 to 4 (each... (5 Replies)
Discussion started by: aberg
5 Replies
LEARN ABOUT OPENSOLARIS
_lwp_sema_trywait
_lwp_sema_wait(2) System Calls _lwp_sema_wait(2)NAME
_lwp_sema_wait, _lwp_sema_trywait, _lwp_sema_init, _lwp_sema_post - semaphore operations
SYNOPSIS
#include <sys/lwp.h>
int _lwp_sema_wait(lwp_sema_t *sema);
int _lwp_sema_trywait(lwp_sema_t *sema);
int _lwp_sema_init(lwp_sema_t *sema, int count);
int _lwp_sema_post(lwp_sema_t *sema);
DESCRIPTION
Conceptually, a semaphore is an non-negative integer count that is atomically incremented and decremented. Typically this represents the
number of resources available. The _lwp_sema_init() function initializes the count, _lwp_sema_post() atomically increments the count, and
_lwp_sema_wait() waits for the count to become greater than 0 and then atomically decrements it.
LWP semaphores must be initialized before use. The _lwp_sema_init() function initializes the count associated with the LWP semaphore
pointed to by sema to count.
The _lwp_sema_wait() function blocks the calling LWP until the semaphore count becomes greater than 0 and then atomically decrements it.
The _lwp_sema_trywait() function atomically decrements the count if it is greater than zero. Otherwise it returns an error.
The _lwp_sema_post() function atomically increments the semaphore count. If there are any LWPs blocked on the semaphore, one is unblocked.
RETURN VALUES
Upon successful completion, 0 is returned. A non-zero value indicates an error.
ERRORS
The _lwp_sema_init(), _lwp_sema_trywait(), _lwp_sema_wait(), and _lwp_sema_post() functions will fail if:
EINVAL The sema argument points to an invalid semaphore.
EFAULT The sema argument points to an illegal address.
The _lwp_sema_wait() function will fail if:
EINTR The function execution was interrupted by a signal or fork(2).
The _lwp_sema_trywait() function will fail if:
EBUSY The function was called on a semaphore with a zero count.
The _lwp_sema_post() function will fail if:
EOVERFLOW The value of the sema argument exceeds SEM_VALUE_MAX.
SEE ALSO fork(2)SunOS 5.11 8 May 1998 _lwp_sema_wait(2)