I am trying to check if the day is Sunday or Friday, and if the time is later than hour 20.
If so, then I want to do something; if not, I want to do something else.
I am using /bin/sh.
This gives me below error:
Too many arguments.
Why ?
day_of_week=$(date -d $given_date +%u )
hour_of_day=${ST_job:0:2}
if [ [ $day_of_week -eq 7 ] || [ [ $day_of_week -eq 5 ] && [ $hour_of_day -gt 20 ] ] ] ; then
something
else
something else
fi
Thanks
You might think "[" is just a grouping, and that you could have different arbitrary nestings.
It isn't.
"[" is an alias for the shell "test" command ... and you need to match them correctly:
https://www.shellscript.sh/test.html
Test is used by virtually every shell script written. It may not seem that way, because test is not often called directly. test is more frequently called as [. [ is a symbolic link to test, just to make shell programs more readable. It is also normally a shell builtin (which means that the shell itself will interpret [ as meaning test, even if your Unix environment is set up differently):
$ type [ [ is a shell builtin $ which [ /usr/bin/[ $ ls -l /usr/bin/[ lrwxrwxrwx 1 root root 4 Mar 27 2000 /usr/bin/[ -> test $ ls -l /usr/bin/test -rwxr-xr-x 1 root root 35368 Mar 27 2000 /usr/bin/test
Look here for more details (and some helpful examples):
Advanced Bash-Scripting Guide: 7.4. Nested if/then Condition Tests
[ is a symlink is not so clear. Some (many? most?) Unixen chose to make it a hard link to test. At least FreeBSD does.The test command (aka [) does not nest. Anything after the first [ is treated as an expression and the one you used is syntactically invalid.
Personally, I find complex tests with [ so ugly, they make me want to find other, more readable and flexible solutions. The case/in syntax can be used here:
case $day_of_week/$hour_of_day in
(7/* | 5/2[123]) echo "something";;
(*) echo "something else";;
esac
|. The "and" condition for day and hour is made by concatenating with a delimiter character (here /) and the appropriate pattern to match: 5/21 only matches when the day is 5 AND the hour is 21. You get the idea?|| and &&, they both have equal precedence and the evaluation is stopped as soon as the result is determined. This is called short-circuiting. true || false does not evaluate the false part. false && true does not evaluate the true part. If you insist on using [ then it is probably more readable to use -o for or and -a for and, along with ( for grouping.Try adjusting your code as following..
day_of_week=$(date -d $given_date +%u )
hour_of_day=${ST_job:0:2}
if [[ $day_of_week -eq 7 || $day_of_week -eq 5 && $hour_of_day -gt 20 ]] ;
then
echo "something"
else
echo "something else"
fi
When putting the arguments in the if condition you don't need to have square brackets again to separate the arguments.
