What `gzip` does.

gzip_strace.txt

$ gzip hej
...
open("hej", O_RDONLY|O_NOCTTY|O_NONBLOCK|O_NOFOLLOW) = 3
fstat(3, {st_mode=S_IFREG|0664, st_size=27, ...}) = 0
rt_sigprocmask(SIG_BLOCK, [HUP INT PIPE TERM XCPU XFSZ], [], 8) = 0
open("hej.gz", O_WRONLY|O_CREAT|O_EXCL, 0600) = 4
rt_sigprocmask(SIG_SETMASK, [], NULL, 8) = 0
read(3, "dsfkjfh'\nsdf\nsdf\nf\ndsf\nsdf\n", 65536) = 27
read(3, "", 65509)                      = 0
write(4, "\37\213\10\10f\215sX\0\3hej\0K)N\313\316J\313P\347*NI\3\3434\256\224b"..., 43) = 43
close(3)                                = 0
utimensat(4, NULL, {{1483967845, 74311372}, {1483967846, 910307585}}, 0) = 0
fchown(4, 1001, 1001)                   = 0
fchmod(4, 0664)                         = 0
close(4)                                = 0
rt_sigprocmask(SIG_BLOCK, [HUP INT PIPE TERM XCPU XFSZ], [], 8) = 0
unlink("hej")
...