[SOLVED] Tcsh

DoME69 · 10-11-2019, 02:10 AM

Hi,

I'm writing in tcsh and try to understand why if can't handle number with '0' in the beginning?

Code:

if ( 09 > 24 ) then...

pan64 · 10-11-2019, 02:39 AM

why? Can you give us a better example?

Ser Olmy · 10-11-2019, 02:40 AM

Seems to work fine here. This:

Code:

if ( 09 > 24 ) then
  echo First number is greater
else
  echo Second number is greater
endif

...returns "Second number is greater", while this:

Code:

if ( 24 > 09 ) then
  echo First number is greater
else
  echo Second number is greater
endif

..returns "First number is greater".

I also tried comparing the numbers "9" and "010" to rule out the possibility that numbers with leading zeros might be interpreted as octal, which is what bash would do.

DoME69 · 10-11-2019, 02:43 AM

Quote:

Originally Posted by Ser Olmy

Seems to work fine here. This:

Code:

if ( 09 > 24 ) then
  echo First number is greater
else
  echo Second number is greater
endif

...returns "Second number is greater", while this:

Code:

if ( 24 > 09 ) then
  echo First number is greater
else
  echo Second number is greater
endif

..returns "First number is greater".

I also tried comparing the numbers "9" and "010" to rule out the possibility that numbers with leading zeros might be interpreted as octal, which is what bash would do.

while running in terminal I get the below error:

Code:

if: Badly formed number.

Ser Olmy · 10-11-2019, 02:52 AM

What does tcsh --version report on your system? And just out of curiosity, does is still complain if only digits 0-7 are used ("if ( 07 > 24 ) then ...")?

If indeed your version of tsch can't handle leading zeroes, it's not a gargantuan task to strip them out before the comparison.

Edit: It seems tcsh versions between 6.14 and 6.17.01 did indeed treat numbers with leading zeroes as octal, just like bash. This broke a few scripts, and the change was rolled back in 6.17.02.

DoME69 · 10-11-2019, 03:12 AM

Quote:

Originally Posted by Ser Olmy

What does tcsh --version report on your system? And just out of curiosity, does is still complain if only digits 0-7 are used ("if ( 07 > 24 ) then ...")?

If indeed your version of tsch can't handle leading zeroes, it's not a gargantuan task to strip them out before the comparison.

Edit: It seems tcsh versions between 6.14 and 6.17.01 did indeed treat numbers with leading zeroes as octal, just like bash. This broke a few scripts, and the change was rolled back in 6.17.02.

Version: tcsh 6.17.00
and 07 instead of 09 work for me.
I guess it's octal number, no?

Ser Olmy · 10-11-2019, 03:14 AM

Quote:

Originally Posted by DoME69

Version: tcsh 6.17.00
and 07 instead of 09 work for me.
I guess it's octal number, no?

Indeed. You need to strip leading zeroes before doing the comparison. That'll work in any version of tsch.

DoME69 · 10-11-2019, 03:39 AM

Thanks @Ser Olmy