Subtracting from multiple columns

[Rjbeckwith]

Hi all, I have a table like this

_time	file1.txt	file2.txt	file3.txt	*.txt
1472160022	1472160022	1472160000	1472160099	...
1472160024	1472160100	1472160300	1472160040	...
...	...	...	...	...

The filename columns are all of the format *.txt but there are so many and they can change in the future that I don't want to hardcode them.
I would like to subtract the *.txt from the the _time column
I basically want to do  

eval *.txt = _time-*.txt

 Which would theoretically give these values:

_time	file1.txt	file2.txt	file3.txt	*.txt
1472160022	0	22	-77	...
1472160024	-76	-276	-16	...
...	...	...	...	...

But I can't seem to wildcard in the subtraction in the eval. Any ideas are much appreciated! 

[scelikok · Accepted solution]

Hi @Rjbeckwith,

Please try below;

| foreach "*.txt" [eval "<<MATCHSTR>>.txt" = _time - '<<FIELD>>' ]

[ITWhisperer]

Try foreach *.txt to apply and operation to each field matching *.txt