Writing a script using bash. I am trying to look through lines in a file for a specific date format:
date +"%a %b %d %T %Z %Y"
For example, if the line were
/foo/bar/foobar this 12 is 411 arbitrary stuff in the line Wed Jun 10 10:10:10 PST 2017
I would want to obtain Wed Jun 10 10:10:10 PST 2017.
Any way to search for specific date formats?
I'm not sure whether you'll agree with this approach. But if this is for some quick, non-recurring work, I won't look for a perfect solution that can handle all the scenarios.
To start with, you can use the following too generic pattern to match the part you want.
cat file | sed -n 's/.*\(... ... .. ..:..:.. ... ....\).*/\1/p'
Then you can enhance this further restricting the matches as you need.
E.g.
cat file | sed -n 's/.*\([a-Z]\{3\} [a-Z]\{3\} [0-3][0-9] [0-2][0-9]:[0-5][0-9]:[0-5][0-9] [A-Z]\{3\} [0-9]\{4\}\).*/\1/p'
Note that this still is not perfect and can match invalid contents. If you find it still not good enough, you can further fine tune the pattern to the point you want.
Related
I have two timestamps in formats :
Timestamp 1 (Variable - RunStartDate): Thu May 3 14:12:54 CDT 2018
Timestamp 2 (Variable - RunEndDate): Thu May 3 18:11:46 CDT 2018
I want the difference of number of hours between these two timestamps in UNIX shell. (I.e. RunEndDate - RunStartDate in hours)
Please help, I am new to UNIX and it is throwing me errors when I just try to subtract the two.
You have a few options here, such as calling out to Perl or Python and using a date/time library to do the math for you. Another option is to use the date program to convert the dates to seconds, subtract the values, and then convert back to hours. Unfortunately, you can't do floating-point math in Bash, so we'll have to call out to a helper program to do that, too.
START=$(date -d "$RunStartDate" +"%s")
END=$(date -d "$RunEndDate" +"%s")
HOURS=$(bc -l <<< "($END - $START) / 3600")
Note that this will only work on GNU systems (e.g. Linux).
How can I learn date and time from the internet using bash without installing anything extra.
I am basically looking for an equivalent of bash $ date, but using an NTP (or any other way) to get the correct date and time from the internet. All the methods I find (such as ntpd) are meant to correct the system time, which is not my purpose.
date has a lot of options for formatting, but I'm assuming that you just want the date and time:
ntpdate -q time.google.com | sed -n 's/ ntpdate.*//p'
(or any other time server)
If you have ntpd installed & configured then you can use the NTP Query command ntpq -crv which will return;
associd=0 status=04ff leap_none, sync_uhf_radio, 15 events, stale_leapsecond_values,
version="ntpd 4.2.6p5#1.2349-o Mon Feb 6 07:22:46 UTC 2017 (1)",
processor="x86_64", system="Linux/4.10.13-1.el6.elrepo.x86_64", leap=00,
stratum=1, precision=-23, rootdelay=0.000, rootdisp=1.000, refid=PPS,
reftime=dd2c9f10.f25911ee Wed, Aug 2 2017 19:57:20.946,
clock=dd2c9f11.f4251b0a Wed, Aug 2 2017 19:57:21.953, peer=6516, tc=4,
mintc=3, offset=-0.005, frequency=-17.045, sys_jitter=0.110,
clk_jitter=0.007, clk_wander=0.003, tai=37, leapsec=201701010000,
expire=201706010000
You want the line starting clock which gives the time, date etc - you would be best parsing this out with awk or something if you just want the date stamp rather then everything else.
You do not need to be a root user to run the command. It won't set anything, but will query your local server (presuming your running ntp) and present the details.
oldest_year_month_temp=201602
NUM_PART_RETAIN=20
oldest_year_month=`date --date="$(oldest_year_month_temp +%Y%m) - $NUM_PART_RETAIN month" "+%Y%m"`
Date is not coming as expected.
One easy way to do it would be to simply append a 01 to your input of yymm to provide a format date -d could read as the starting date, then simply subtract 20 months and output the resulting date in %y%m format. For example, if you provide the date 9910 (Oct. 1999), you can do:
$ date -d "991001 - 20 months" +%y%m
9802
Which returns Feb. 1998 (20 months earlier)
(note: the $ above just indicates a command by a normal user as opposed to # indicating a command by the super user (e.g. root))
Inside the $(...) there must be a command, e.g. $(date ...).
This should have been obvious from the error message you got, which was probably oldest_year_month_temp: no such command.
When reading from a variable, you must write a $ before its name.
I have a large number of downloaded radio programs that consist of 4 mp3 files each. The files are named like so:
Show Name - Nov 28 2011 - Hour 1.mp3
Show Name - Nov 28 2011 - Hour 2.mp3
Show Name - Nov 28 2011 - Hour 3.mp3
Show Name - Nov 28 2011 - Hour 4.mp3
Show Name - Nov 29 2011 - Hour 1.mp3
Show Name - Nov 29 2011 - Hour 2.mp3
Show Name - Nov 29 2011 - Hour 3.mp3
Show Name - Nov 29 2011 - Hour 4.mp3
Show Name - Nov 30 2011 - Hour 1.mp3 and so on...
I have used the cat command to join the files with great success by moving the four files of the same date into a folder and using the wildcard:
cat *.mp3 > example.mp3
The files are all the same bitrate, sampling rate, etc.
What I would like to do is run a script that will look at the file name and combine hours 1-4 of each date and name the file accordingly. Just the show name, the date and drop the 'Hour 1'.
I looked around and found a number of scripts that can be used to move files around based on their names but I'm not adept enough at bash scripting to be able to understand the methods used and adapt them to my needs.
I'm using Ubuntu 14.04.
Many thanks in advance
You can use a bash for loop to find each distinct date name and then construct the expected mp3 names from that.
Because your files have spaces in their names and my solution uses globbing, you'll also have to edit your Internal Field Separator to ignore spaces for the duration of the script.
SAVEIFS=$IFS
IFS=$'\n\b'
for mdy in `/bin/ls *mp3 | cut -d' ' -f'4,5,6' | sort -u`; do
cat *${mdy}*.mp3 > "showName_${mdy}_full.mp3"
done
IFS=$SAVEIFS
This won't alert you if some hours are missing for some particular date. It'll just join together whatever's there for that date.
Note: The comment pointing out that cat probably won't work for these files is spot on. The resulting file will probably be corrupted. You probably want to use something like mencoder or ffmpeg instead. (Check out this thread.)
I am trying to shift the dates of a series of files by 9 hours. I've reached as far as this:
for i in *.MOV; do touch -r "$i" -d "-9 hours" "$i"; done
This should work in recent systems, but the touch command in OSX seems to be a bit outdated and not to support the -d switch.
I'm using Snow Leopard. Any idea on the best option for doing this with a single line command? I don't want to create a script for this.
Ok, sorted it out. OSX comes with a gtouch command, that knows the -d switch. It's part of GNU coreutils. See the comments below for information regarding availability on specific MacOS versions.
For more information on using relative dates with the -d switch see the manual.
Looking at the Wikipedia Page for Touch, it appears you're accustomed to the GNU version of Touch. Which MacOS isn't using.
For what you want to do, look into the "SetFile" command, which gets installed with XCode tools. You have -d and -m options, which reset the Created and Modified dates & times respectively.
http://developer.apple.com/library/mac/#documentation/Darwin/Reference/ManPages/man1/SetFile.1.html
Donno OS X, but it should be easy enough to
get curr time stamp on the file
convert it to seconds
subtract 9 hours (9*60*60 secs) from it
convert it back to the format accepted by touch's -t option
run touch command
All this of course can be done in a single for loop on command line.
Here are simple examples from WikiPedia showing back and forth conversion.
# To convert a specific time stamp to Unix epoch time (seconds since 1970-01-01):
date +"%s" -d "Fri Apr 24 13:14:39 CDT 2009"
# 1240596879
# To convert Unix epoch time (seconds since 1970-01-01) to a human readable format:
date -d "UTC 1970-01-01 1240596879 secs"
# Fri Apr 24 13:14:39 CDT 2009
# Or:
date -ud #1000000000
# Sun Sep 9 01:46:40 UTC 2001
# or: Haven't tested this but should work..
date -d #1000000000 +%y%m%d%%H%M%S
# 010909014640