Re: Why doesn't "cat a b > foo" work?

2021-01-19 Thread Christophe Leroy
Le 19/01/2021 à 23:17, Grant Edwards a écrit : On 2021-01-19, Grant Edwards wrote: I've confirmed that with our older version of busybox (1.26?) 'cat' doesn't use sendfile() for the test case above (which works fine). AFAICT from the strace output the sendfile64() call is made correctly, so

Re: Why doesn't "cat a b > foo" work?

2021-01-19 Thread Grant Edwards
On 2021-01-19, Grant Edwards wrote: > I've confirmed that with our older version of busybox (1.26?) 'cat' > doesn't use sendfile() for the test case above (which works > fine). AFAICT from the strace output the sendfile64() call is made > correctly, so it must be a kernel problem and not a gcc

Re: Why doesn't "cat a b > foo" work?

2021-01-19 Thread Grant Edwards
On 2021-01-19, Grant Edwards wrote: > We recently upgraded from an older version of busybox to 1.31.0, and > now there seems to be a problem with 'cat'. If I cat two files to > stdout it works fine, but if I redirect output into a file using ash, > the second file overwrites the first: > > #

Why doesn't "cat a b > foo" work?

2021-01-19 Thread Grant Edwards
We recently upgraded from an older version of busybox to 1.31.0, and now there seems to be a problem with 'cat'. If I cat two files to stdout it works fine, but if I redirect output into a file using ash, the second file overwrites the first: # echo abcdefghijk > a # echo 12345 > b