Probably a simple one.
Basically I am retrieving a number from a file - setting a variable against it and then incrementing this by 1 and using this as an entry number in a log file for messages. I need the variable to re-evalute itself each time I call it so I get the latest number in the file -... (1 Reply)
I'm not very familiar with the ssh command. When I tried to set a variable and then echo its value on a remote machine via ssh, I found a problem. For example,
$ ITSME=itsme
$ ssh xxx.xxxx.xxx.xxx "ITSME=itsyou; echo $ITSME"
itsme
$ ssh xxx.xxxx.xxx.xxx 'ITSME=itsyou; echo $ITSME'
itsyou
$... (3 Replies)
I have variables:
FOO="Text"
BAR="FOO"
I'd like to be able to evaluate the variable named as the value of $BAR.
echo $FOO
Text
echo $BAR
FOO
This is what I'd like to do:
echo ${$BAR} (this won't work)
Text (3 Replies)
Hi guys, I have a sed line in double quotes which works fine, but I want it to be in single quotes
here is the sed line
sed "/abc_def/s/\'.*\'/\'\${abc_def}\'/"
can some one give the equivalent to the above script in single quotes
Thanks a ton (5 Replies)
Unix superusers,
I am new to unix but would like to learn more about grep. I am very familiar with regular expressions as i have used them for searching text files in windows based text editors. Since I am not very familiar with Unix, I dont understand when one should use GREP with the... (2 Replies)
Hello. I'm trying to write a bash script that uses GNU screen and have hit a brick wall that has cost me many hours... (I'm sure it has something to do with quoting/globbing, which is why I post it here)
I can make a script that does the following just fine:
test.sh:
#!/bin/bash
# make... (2 Replies)
How to evaluate the value of a variable ?
For example:
a=var
$a=value !!!error happens!!!
I want to evaluate var=value, how to realize it?
Thanks!
---------- Post updated at 03:37 AM ---------- Previous update was at 02:22 AM ----------
I am using linux bash.
a=var
$a=value... (4 Replies)
In BASH, how does ||: get interpreted. I know || is logical or. And I believe : evaluates to true. Can someone give a thorough explanation for this usage?
Example
for i in $IGGY
do
&& skipdb=1 || : (6 Replies)
Hi,
Trying to change the prompt. I have the following code.
export PS1='
<${USER}@`hostname -s`>$ '
The hostname is not displayed
<abc@`hostname -s`>$ uname -a
AIX xyz 1 6 00F736154C00
<adcwl4h@`hostname -s`>$
If I use double quotes, then the hostname is printed properly but... (3 Replies)
Hi All,
I'm unable to load the data using sql loader where there are double quotes within the double quotes As these are optionally enclosed by double quotes.
Sample Data :
"221100",138.00,"D","0019/1477","44012075","49938","49938/15043000","Television - 22" Refurbished - Airwave","Supply... (6 Replies)
Discussion started by: mlavanya
6 Replies
LEARN ABOUT OPENDARWIN
cron
cron(1M) System Administration Commands cron(1M)NAME
cron - clock daemon
SYNOPSIS
/usr/sbin/cron
DESCRIPTION
cron starts a process that executes commands at specified dates and times.
You can specify regularly scheduled commands to cron according to instructions found in crontab files in the directory
/var/spool/cron/crontabs. Users can submit their own crontab file using the crontab(1) command. Commands which are to be executed only once
can be submitted using the at(1) command.
cron only examines crontab or at command files during its own process initialization phase and when the crontab or at command is run. This
reduces the overhead of checking for new or changed files at regularly scheduled intervals.
As cron never exits, it should be executed only once. This is done routinely by way of the svc:/system/cron:default service. The file
/etc/cron.d/FIFO file is used as a lock file to prevent the execution of more than one instance of cron.
cron captures the output of the job's stdout and stderr streams, and, if it is not empty, mails the output to the user. If the job does not
produce output, no mail is sent to the user. An exception is if the job is an at(1) job and the -m option was specified when the job was
submitted.
cron and at jobs are not executed if your account is locked. Jobs and processses execute. The shadow(4) file defines which accounts are not
locked and will have their jobs and processes executed.
Setting cron Jobs Across Timezones
The timezone of the cron daemon sets the system-wide timezone for cron entries. This, in turn, is by set by default system-wide using
/etc/default/init.
If some form of daylight savings or summer/winter time is in effect, then jobs scheduled during the switchover period could be executed
once, twice, or not at all.
Setting cron Defaults
To keep a log of all actions taken by cron, you must specify CRONLOG=YES in the /etc/default/cron file. If you specify CRONLOG=NO, no log-
ging is done. Keeping the log is a user configurable option since cron usually creates huge log files.
You can specify the PATH for user cron jobs by using PATH= in /etc/default/cron. You can set the PATH for root cron jobs using SUPATH= in
/etc/default/cron. Carefully consider the security implications of setting PATH and SUPATH.
Example /etc/default/cron file:
CRONLOG=YES
PATH=/usr/bin:/usr/ucb:
This example enables logging and sets the default PATH used by non-root jobs to /usr/bin:/usr/ucb:. Root jobs continue to use
/usr/sbin:/usr/bin.
The cron log file is periodically rotated by logadm(1M).
FILES
/etc/cron.d Main cron directory
/etc/cron.d/FIFO Lock file
/etc/default/cron cron default settings file
/var/cron/log cron history information
/var/spool/cron Spool area
/etc/cron.d/queuedefs Queue description file for at, batch, and cron
/etc/logadm.conf Configuration file for logadm
ATTRIBUTES
See attributes(5) for descriptions of the following attributes:
+-----------------------------+-----------------------------+
| ATTRIBUTE TYPE | ATTRIBUTE VALUE |
+-----------------------------+-----------------------------+
|Availability |SUNWcsu |
+-----------------------------+-----------------------------+
SEE ALSO svcs(1), at(1), crontab(1), sh(1), logadm(1M), svcadm(1M), queuedefs(4), shadow(4), attributes(5), smf(5)NOTES
The cron service is managed by the service management facility, smf(5), under the service identifier:
svc:/system/cron:default
Administrative actions on this service, such as enabling, disabling, or requesting restart, can be performed using svcadm(1M). The ser-
vice's status can be queried using the svcs(1) command.
DIAGNOSTICS
A history of all actions taken by cron is stored in /var/cron/log and possibly in /var/cron/olog.
SunOS 5.10 5 Aug 2004 cron(1M)