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Unix Commands
DataStage Stages

DataStage Concepts

DataStage Migration

Tutorial Videos(YouTube)

Oracle Queries

UNIX : Date and Time Syntax

Date & Time Syntax

The syntax is

date +FORMAT

date +"%FORMAT"

date +"%FORMAT%FORMAT"

date +"%FORMAT-%FORMAT"

Display date

Date in mm-dd-yy format:

$ date +"%m-%d-%y"
Output: 02-27-07

Date as mm/dd/yy format:

date +"%D"

Date as Tuesday-03-December-13

date +%A-%d-%B-%y

Output: Tuesday-03-December-13

Date as Tuesday-03-Dec-13

date +%A%_d-%b-%y

Output: Tuesday 3-Dec-13

Date as mm/dd/yyyy format:

date +"%m/%d/%Y"

Display time only

Type the following command:
$ date +"%T"
Outputs: 19:55:04

To display locale's 12-hour clock time, enter:
$ date +"%r"
Outputs: 07:56:05 PM

To display time in HH:MM format, type:
$ date +"%H-%M"
Sample outputs: 00-50

A complete list of FORMAT control characters supported by the date command

FORMAT controls the output. It can be the combination of any one of the following:

%FORMAT String	Description
%%	a literal %
%a	locale's abbreviated weekday name (e.g., Sun)
%A	locale's full weekday name (e.g., Sunday)
%b	locale's abbreviated month name (e.g., Jan)
%B	locale's full month name (e.g., January)
%c	locale's date and time (e.g., Thu Mar 3 23:05:25 2005)
%C	century; like %Y, except omit last two digits (e.g., 21)
%d	day of month (e.g, 01)
%D	date; same as %m/%d/%y
%e	day of month, space padded; same as %_d
%F	full date; same as %Y-%m-%d
%g	last two digits of year of ISO week number (see %G)
%G	year of ISO week number (see %V); normally useful only with %V
%h	same as %b
%H	hour (00..23)
%I	hour (01..12)
%j	day of year (001..366)
%k	hour ( 0..23)
%l	hour ( 1..12)
%m	month (01..12)
%M	minute (00..59)
%n	a newline
%N	nanoseconds (000000000..999999999)
%p	locale's equivalent of either AM or PM; blank if not known
%P	like %p, but lower case
%r	locale's 12-hour clock time (e.g., 11:11:04 PM)
%R	24-hour hour and minute; same as %H:%M
%s	seconds since 1970-01-01 00:00:00 UTC
%S	second (00..60)
%t	a tab
%T	time; same as %H:%M:%S
%u	day of week (1..7); 1 is Monday
%U	week number of year, with Sunday as first day of week (00..53)
%V	ISO week number, with Monday as first day of week (01..53)
%w	day of week (0..6); 0 is Sunday
%W	week number of year, with Monday as first day of week (00..53)
%x	locale's date representation (e.g., 12/31/99)
%X	locale's time representation (e.g., 23:13:48)
%y	last two digits of year (00..99)
%Y	year
%z	+hhmm numeric timezone (e.g., -0400)
%:z	+hh:mm numeric timezone (e.g., -04:00)
%::z	+hh:mm:ss numeric time zone (e.g., -04:00:00)
%:::z	numeric time zone with : to necessary precision (e.g., -04, +05:30)
%Z	alphabetic time zone abbreviation (e.g., EDT)

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UNIX: Remove CTRL-M

Remove CTRL-M characters from a file in UNIX

Type this command:

sed -e "s/^M//" filename > newfilename

To enter ^M, type CTRL-V, then CTRL-M.

That is, hold down the CTRL key then press V and M in succession.

Easiest option Remove CTRL-M characters from a file in UNIX

cat test1.txt | col -b > newfilename.txt

UNIX: CRON Scheduler

CRON Scheduler

cron is a unix, solaris utility that allows tasks to be automatically run in the background at regular intervals by the cron daemon. These tasks are often termed as cron jobs in unix , solaris.  Crontab (CRON TABle) is a file which contains the schedule of cron entries to be run and at specified times

Crontab Restrictions

You can execute crontab if your name appears in the file /usr/lib/cron/cron.allow. If that file does not exist, you can use
crontab if your name does not appear in the file /usr/lib/cron/cron.deny.
If only cron.deny exists and is empty, all users can use crontab. If neither file exists, only the root user can use crontab. The allow/deny files consist of one user name per line.

Crontab Commands

export EDITOR=vi ;to specify a editor to open crontab file.

crontab -e    Edit your crontab file, or create one if it doesn’t already exist.
crontab -l      Display your crontab file.
crontab -r      Remove your crontab file.
crontab -v      Display the last time you edited your crontab file. (This option is only available on a few systems.)

Crontab file

Crontab syntax:
A crontab file has five fields for specifying day, date and time followed by the command to be run at that interval.

Several special predefined values can substitute in the cron expression. Note that in some uses of the cron format there is also a seconds field at the beginning of the pattern (e.g. Quartz).

Entry	Description	Equivalent to
@yearly (or @annually)	Run once a year at midnight in the morning of January 1	0 0 1 1 *
@monthly	Run once a month at midnight in the morning of the first day of the month	0 0 1 * *
@weekly	Run once a week at midnight in the morning of Sunday	0 0 * * 0
@daily	Run once a day at midnight	0 0 * * *
@hourly	Run once an hour at the beginning of the hour	0 * * * *
@reboot	Run at startup	@reboot

*     *     *   *    *        command to be executed -     -     -   -    - |     |     |   |    | |     |     |   |    +----- day of week (0 - 6) (Sunday=0) |     |     |   +------- month (1 - 12) |     |     +--------- day of the month (1 - 31) |     +----------- hour (0 - 23) +------------- min (0 - 59)

Sunday               -0

Monday             -1

Tuesday             -2

Wednesday       -3

Thursday           -4

Friday                -5

Saturday            -6

* In the value field above means all legal values as in braces for that column.
The value column can have a * or a list of elements separated by commas. An element is either a number in the ranges shown above or two numbers in the range separated by a hyphen (meaning an inclusive range).

Notes
A.) Repeat pattern like /2 for every 2 minutes or /10 for every 10 minutes is not supported by all operating systems. If you try to use it and crontab complains it is probably not supported.

B.) The specification of days can be made in two fields: month day and weekday. If both are specified in an entry, they are cumulative meaning both of the entries will get executed.

Crontab Example

A line in crontab file like below removes the tmp files from /home/someuser/tmp each day at 6:30 PM.

30     18     *     *     *         rm /home/someuser/tmp/*

Changing the parameter values as below will cause this command to run at different time schedule below:

min	hour	day/month	month	day/week	Execution time
30	0	1	1,6,12	*	– 00:30 Hrs  on 1st of Jan, June & Dec.
0	20	*	10	1-5	–8.00 PM every weekday (Mon-Fri) only in Oct.
0	0	1,10,15	*	*	– midnight on 1st ,10th & 15th of month
5,10	0	10	*	1	– At 12.05,12.10 every Monday & on 10th of every month

Note: If you inadvertently enter the crontab command with no argument(s), do not attempt to get out with Control-d. This removes all entries in your crontab file. Instead, exit with Control-c.

Crontab Environment

cron invokes the command from the user’s HOME directory with the shell, (/usr/bin/sh).
cron supplies a default environment for every shell, defining:
HOME=user’s-home-directory
LOGNAME=user’s-login-id
PATH=/usr/bin:/usr/sbin:.
SHELL=/usr/bin/sh

Users who desire to have their .profile executed must explicitly do so in the crontab entry or in a script called by the entry.

Disable Email

By default cron jobs sends a email to the user account executing the cronjob. If this is not needed put the following command at the end of the cron job line.

>/dev/null 2>&1

Generate log file

To collect the cron execution log in a file:

30 18 * * * rm /home/someuser/tmp/* > /home/someuser/cronlogs/clean_tmp_dir.log