display number of days in current month

Shell Programming and Scripting
1

hi all

searched google and here, cant find and am begining to suspect there is no options for this.

shell = born

with either the date or cal command I need to display the number of days in current month. can anyone point me in the right direction?

2 
cal | nawk 'FNR>2{d+=NF}END{print d}'
3

thanks..

I get nawk not found

4

so use 'awk' instead.....

5

sorry I got it now.. thanks a bunch for the help

6

How about:

days=$(($(cal | wc -w) - 9))

Takes away 9 because of 7xDoW_heading + 1xmonth + 1xyear

or pull last word on the last line with sed:

days=$(cal | sed -n '/[23]/h;${x;s/.* //p;}')
7 
# cal | sed 'N;N;N;N;N;N;N;s/\n//g;s/.*\(..\)$/\1/'
31

# cal | awk 'NF{x=$NF}END{print x}'
31

---------- Post updated at 12:34 AM ---------- Previous update was at 12:33 AM ----------

# cal | xargs -n1 | tail -1
31

@Schubler: in some case, yours sed solution doesn't work as expected :

# cal 7 2011 | sed 'N;N;N;N;N;N;N;s/\n//g;s/.*\(..\)$/\1/'
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# cal 7 2011 | sed -n '/[23]/h;${x;s/.* //p;}'
#

i got the same behaviour in linux & solaris

Some others:

# v=$(cal)
# echo ${v##* }
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# echo $(cal) | tail -c 3
31
1 Like
8

wow thanks guys

9

hehehe, so many ways to skin a cat.

@ctsgnb, thanks was my sed solution - fix was pretty simple:

# cal 7 2011 | sed -n '/[23]/h;${x;s/.* //;p}'
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10

Hehe yes,

@Schubler,

Your fix works on linux... but it requires an additional little semicolon fix to work on the solaris 10 i have tryied (i think FreeBSD has the same kind of need of ending semicolon before "}" ... so in fact better to keep both of the semicolon before and after the p

$ uname -a
SunOS xxxxxx 5.10 Generic_141414-01 sun4u sparc SUNW,Sun-Fire-V490
$ cal 7 2011 | sed -n '/[23]/h;${x;s/.* //;p}'
sed: command garbled: /[23]/h;${x;s/.* //;p}
$ cal 7 2011 | sed -n '/[23]/h;${x;s/.* //;p;}'
31
$

another one for the fun ...

$ echo $(cal) | tail -c 3
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or if running solaris

$ echo $(cal) | /usr/xpg4/bin/tail -c 3
31
11

Using FreeBSD Man Page for date (FreeBSD Section 0) - The UNIX and Linux Forums

# uname
FreeBSD
# date
Tue Mar 15 21:05:40 EDT 2011
# date -v 1d -v +1m  -v -1d "+%A %B %d %Y"                           # First day of (current month+1) minus 1 day.
Thursday March 31 2011
# date -v 1d -v +1m  -v -1d "+%d"
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