Bash 为什么Perl'；s print无法将任何内容输出到STDOUT和STDERR，但成功写入文件？

我试图从下面的Perl脚本打印到标准输出，但它不会在屏幕上产生任何输出。但是，它会打印到文件中

#!/usr/bin/perl
use warnings;
use strict;

print "Here's some text\n";
print STDERR "Here's some text\n";
print STDOUT "Here's some text\n";

open FH, ">", "file.txt" or die $!;

print FH "Here's some text\n";

我尝试检查我正在使用的perl版本（

perl-v

），但也没有输出任何内容。perl手册页告诉我我正在使用5.14.2。我正在从Raspberry Pi的bash提示符运行Perl脚本

我看到了这篇类似的文章，所以我使用了strace，并且看到输出没有包含任何写命令

strace perl -we'print("a") or die("Can'\''t print: $!\n");'

以下是完整脚本的strace输出：

execve("./response", ["./response"], [/* 18 vars */]) = 0
brk(0)                                  = 0xd98000
uname({sys="Linux", node="raspberrypi", ...}) = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
mmap2(NULL, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6f99000
access("/etc/ld.so.preload", R_OK)      = 0
open("/etc/ld.so.preload", O_RDONLY)    = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=44, ...}) = 0
mmap2(NULL, 44, PROT_READ|PROT_WRITE, MAP_PRIVATE, 3, 0) = 0xb6f98000
close(3)                                = 0
open("/usr/lib/arm-linux-gnueabihf/libcofi_rpi.so", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\270\4\0\0004\0\0\0"..., 512) = 512
lseek(3, 7276, SEEK_SET)                = 7276
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1080) = 1080
lseek(3, 7001, SEEK_SET)                = 7001
read(3, "A.\0\0\0aeabi\0\1$\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 47) = 47
fstat64(3, {st_mode=S_IFREG|0755, st_size=10170, ...}) = 0
mmap2(NULL, 39740, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6f6c000
mprotect(0xb6f6e000, 28672, PROT_NONE)  = 0
mmap2(0xb6f75000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1) = 0xb6f75000
close(3)                                = 0
munmap(0xb6f98000, 44)                  = 0
open("/etc/ld.so.cache", O_RDONLY)      = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=64456, ...}) = 0
mmap2(NULL, 64456, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6f5c000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/usr/lib/libperl.so.5.14", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\220\v\2\0004\0\0\0"..., 512) = 512
lseek(3, 1346508, SEEK_SET)             = 1346508
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1120) = 1120
lseek(3, 1346184, SEEK_SET)             = 1346184
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 51) = 51
fstat64(3, {st_mode=S_IFREG|0644, st_size=1347628, ...}) = 0
mmap2(NULL, 1379192, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6e0b000
mprotect(0xb6f4f000, 32768, PROT_NONE)  = 0
mmap2(0xb6f57000, 20480, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x144) = 0xb6f57000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libdl.so.2", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0(\t\0\0004\0\0\0"..., 512) = 512
lseek(3, 8652, SEEK_SET)                = 8652
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1160) = 1160
lseek(3, 8320, SEEK_SET)                = 8320
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0644, st_size=9812, ...}) = 0
mmap2(NULL, 41136, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6e00000
mprotect(0xb6e02000, 28672, PROT_NONE)  = 0
mmap2(0xb6e09000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1) = 0xb6e09000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libm.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\3201\0\0004\0\0\0"..., 512) = 512
lseek(3, 426468, SEEK_SET)              = 426468
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1160) = 1160
lseek(3, 426136, SEEK_SET)              = 426136
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0644, st_size=427628, ...}) = 0
mmap2(NULL, 458912, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6d8f000
mprotect(0xb6df7000, 28672, PROT_NONE)  = 0
mmap2(0xb6dfe000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x67) = 0xb6dfe000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libpthread.so.0", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\274V\0\0004\0\0\0"..., 512) = 512
lseek(3, 82712, SEEK_SET)               = 82712
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1400) = 1400
lseek(3, 82308, SEEK_SET)               = 82308
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0755, st_size=116462, ...}) = 0
mmap2(NULL, 123412, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6d70000
mprotect(0xb6d84000, 28672, PROT_NONE)  = 0
mmap2(0xb6d8b000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x13) = 0xb6d8b000
mmap2(0xb6d8d000, 4628, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d8d000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libc.so.6", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\214y\1\0004\0\0\0"..., 512) = 512
lseek(3, 1215264, SEEK_SET)             = 1215264
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1360) = 1360
lseek(3, 1214828, SEEK_SET)             = 1214828
read(3, "A.\0\0\0aeabi\0\1$\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 47) = 47
fstat64(3, {st_mode=S_IFREG|0755, st_size=1216624, ...}) = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6f98000
mmap2(NULL, 1258784, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6c3c000
mprotect(0xb6d62000, 32768, PROT_NONE)  = 0
mmap2(0xb6d6a000, 12288, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x126) = 0xb6d6a000
mmap2(0xb6d6d000, 9504, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6d6d000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libcrypt.so.1", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0\30\7\0\0004\0\0\0"..., 512) = 512
lseek(3, 29116, SEEK_SET)               = 29116
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1160) = 1160
lseek(3, 28780, SEEK_SET)               = 28780
read(3, "A0\0\0\0aeabi\0\1&\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 49) = 49
fstat64(3, {st_mode=S_IFREG|0644, st_size=30276, ...}) = 0
mmap2(NULL, 221504, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6c05000
mprotect(0xb6c0c000, 28672, PROT_NONE)  = 0
mmap2(0xb6c13000, 8192, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x6) = 0xb6c13000
mmap2(0xb6c15000, 155968, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_ANONYMOUS, -1, 0) = 0xb6c15000
close(3)                                = 0
access("/etc/ld.so.nohwcap", F_OK)      = -1 ENOENT (No such file or directory)
open("/lib/arm-linux-gnueabihf/libgcc_s.so.1", O_RDONLY) = 3
read(3, "\177ELF\1\1\1\0\0\0\0\0\0\0\0\0\3\0(\0\1\0\0\0`\364\0\0004\0\0\0"..., 512) = 512
lseek(3, 130212, SEEK_SET)              = 130212
read(3, "\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"..., 1160) = 1160
lseek(3, 129880, SEEK_SET)              = 129880
read(3, "A2\0\0\0aeabi\0\1(\0\0\0\0056\0\6\6\10\1\t\1\n\2\22\4\24\1\25"..., 51) = 51
fstat64(3, {st_mode=S_IFREG|0644, st_size=131372, ...}) = 0
mmap2(NULL, 162704, PROT_READ|PROT_EXEC, MAP_PRIVATE|MAP_DENYWRITE, 3, 0) = 0xb6bdd000
mprotect(0xb6bfd000, 28672, PROT_NONE)  = 0
mmap2(0xb6c04000, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_FIXED|MAP_DENYWRITE, 3, 0x1f) = 0xb6c04000
close(3)                                = 0
mmap2(NULL, 4096, PROT_READ|PROT_WRITE, MAP_PRIVATE|MAP_ANONYMOUS, -1, 0) = 0xb6f97000
set_tls(0xb6f976d0, 0xb6f97da8, 0xb6f9c048, 0xb6f976d0, 0xb6f9c048) = 0
mprotect(0xb6c13000, 4096, PROT_READ)   = 0
mprotect(0xb6d6a000, 8192, PROT_READ)   = 0
mprotect(0xb6d8b000, 4096, PROT_READ)   = 0
mprotect(0xb6dfe000, 4096, PROT_READ)   = 0
mprotect(0xb6e09000, 4096, PROT_READ)   = 0
mprotect(0xb6f57000, 8192, PROT_READ)   = 0
mprotect(0x11000, 4096, PROT_READ)      = 0
mprotect(0xb6f9b000, 4096, PROT_READ)   = 0
munmap(0xb6f5c000, 64456)               = 0
set_tid_address(0xb6f97278)             = 12607
set_robust_list(0xb6f97280, 0xc)        = 0
futex(0xbece6778, FUTEX_WAIT_BITSET_PRIVATE|FUTEX_CLOCK_REALTIME, 1, NULL, b6d8c000) = -1 EAGAIN (Resource temporarily unavailable)
rt_sigaction(SIGRTMIN, {0xb6d7520c, [], SA_SIGINFO|0x4000000}, NULL, 8) = 0
rt_sigaction(SIGRT_1, {0xb6d750b4, [], SA_RESTART|SA_SIGINFO|0x4000000}, NULL, 8) = 0
rt_sigprocmask(SIG_UNBLOCK, [RTMIN RT_1], NULL, 8) = 0
getrlimit(RLIMIT_STACK, {rlim_cur=8192*1024, rlim_max=RLIM_INFINITY}) = 0
rt_sigaction(SIGFPE, {SIG_IGN, [FPE], SA_RESTART|0x4000000}, {SIG_DFL, [], 0}, 8) = 0
brk(0)                                  = 0xd98000
brk(0xdb9000)                           = 0xdb9000
getuid32()                              = 1001
geteuid32()                             = 1001
getgid32()                              = 1004
getegid32()                             = 1004
open("/usr/lib/locale/locale-archive", O_RDONLY|O_LARGEFILE) = 3
fstat64(3, {st_mode=S_IFREG|0644, st_size=1534656, ...}) = 0
mmap2(NULL, 1534656, PROT_READ, MAP_PRIVATE, 3, 0) = 0xb6a66000
close(3)                                = 0
open("/dev/urandom", O_RDONLY|O_LARGEFILE) = 3
read(3, "~\210\223\234", 4)             = 4
close(3)                                = 0
gettimeofday({1460938704, 307768}, NULL) = 0
readlink("/proc/self/exe", "/usr/bin/perl", 4095) = 13
stat64("/usr/local/lib/site_perl/5.14.2/arm-linux-gnueabihf-thread-multi-64int", 0xbece6368) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/site_perl/5.14.2", 0xbece6368) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/site_perl/arm-linux-gnueabihf-thread-multi-64int", 0xbece6368) = -1 ENOENT (No such file or directory)
open("./response", O_RDONLY|O_LARGEFILE) = 3
ioctl(3, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbece627c) = -1 ENOTTY (Inappropriate ioctl for device)
_llseek(3, 0, [0], SEEK_CUR)            = 0
fcntl64(3, F_SETFD, FD_CLOEXEC)         = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
brk(0xddb000)                           = 0xddb000
read(3, "#!/usr/bin/perl\nuse warnings;\nus"..., 8192) = 210
stat64("/etc/perl/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/etc/perl/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/perl/5.14.2/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/perl/5.14.2/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/perl/5.14.2/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/perl/5.14.2/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl5/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl5/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl/5.14/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl/5.14/warnings.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl/5.14/warnings.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl/5.14/warnings.pm", {st_mode=S_IFREG|0644, st_size=15015, ...}) = 0
open("/usr/share/perl/5.14/warnings.pm", O_RDONLY|O_LARGEFILE) = 4
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbece5be4) = -1 ENOTTY (Inappropriate ioctl for device)
_llseek(4, 0, [0], SEEK_CUR)            = 0
read(4, "# -*- buffer-read-only: t -*-\n# "..., 8192) = 8192
read(4, "08\\x00\\x00\\x00\\x00\\x00\\x00\\x00\\x"..., 8192) = 6823
read(4, "", 8192)                       = 0
close(4)                                = 0
brk(0xdfc000)                           = 0xdfc000
stat64("/etc/perl/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/etc/perl/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/perl/5.14.2/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/local/lib/perl/5.14.2/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/perl/5.14.2/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/local/share/perl/5.14.2/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl5/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl5/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl5/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl/5.14/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/lib/perl/5.14/strict.pm", 0xbece5d90) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl/5.14/strict.pmc", 0xbece5e10) = -1 ENOENT (No such file or directory)
stat64("/usr/share/perl/5.14/strict.pm", {st_mode=S_IFREG|0644, st_size=879, ...}) = 0
open("/usr/share/perl/5.14/strict.pm", O_RDONLY|O_LARGEFILE) = 4
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbece5be4) = -1 ENOTTY (Inappropriate ioctl for device)
_llseek(4, 0, [0], SEEK_CUR)            = 0
read(4, "package strict;\n\n$strict::VERSIO"..., 8192) = 879
_llseek(4, 878, [878], SEEK_SET)        = 0
_llseek(4, 0, [878], SEEK_CUR)          = 0
close(4)                                = 0
read(3, "", 8192)                       = 0
open("file.txt", O_WRONLY|O_CREAT|O_TRUNC|O_LARGEFILE, 0666) = 4
ioctl(4, SNDCTL_TMR_TIMEBASE or TCGETS, 0xbece614c) = -1 ENOTTY (Inappropriate ioctl for device)
_llseek(4, 0, [0], SEEK_CUR)            = 0
fstat64(4, {st_mode=S_IFREG|0644, st_size=0, ...}) = 0
fcntl64(4, F_SETFD, FD_CLOEXEC)         = 0
rt_sigaction(SIG_0, NULL, {0xb6e18dc4, [TRAP RTMIN RT_1 RT_2 RT_3 RT_12 RT_13 RT_15 RT_16 RT_18 RT_19 RT_20 RT_25 RT_26 RT_27 RT_28 RT_29], SA_SIGINFO|0x85b8}, 8) = -1 EINVAL (Invalid argument)
rt_sigaction(SIGHUP, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGINT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGQUIT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGILL, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTRAP, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGABRT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGBUS, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGFPE, NULL, {SIG_IGN, [FPE], SA_RESTART|0x4000000}, 8) = 0
rt_sigaction(SIGKILL, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGUSR1, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGSEGV, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGUSR2, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGPIPE, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGALRM, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTERM, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGSTKFLT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGCONT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGSTOP, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTSTP, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTTIN, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGTTOU, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGURG, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGXCPU, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGXFSZ, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGVTALRM, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGPROF, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGWINCH, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGIO, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGPWR, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGSYS, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_2, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_3, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_4, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_5, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_6, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_7, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_8, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_9, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_10, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_11, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_12, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_13, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_14, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_15, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_16, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_17, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_18, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_19, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_20, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_21, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_22, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_23, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_24, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_25, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_26, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_27, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_28, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_29, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_30, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_31, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGRT_32, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGABRT, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGCHLD, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGIO, NULL, {SIG_DFL, [], 0}, 8) = 0
rt_sigaction(SIGSYS, NULL, {SIG_DFL, [], 0}, 8) = 0
write(4, "Here's some text\n", 17)      = 17
close(4)                                = 0
close(3)                                = 0
exit_group(0)                           = ?

你知道为什么它不能产出吗？bash脚本可以将文本回显到标准输出

当我在调试模式下运行脚本时，它会打印输出

在命令行执行perl-v后，退出$的代码？是0

执行

perl -e'print "foo" or die $!' 

给出和退出代码9，但这似乎是由于模具。perl-v>文件没有向该文件写入任何内容

下面是stat STDOUT的输出以及用于将其写入文件的命令：

45826 | 261126 | 33188 | 1 | 1001 | 1004 | 0 | 1461024408 | 1461035504 | 1461035504 | 4096 | 0

perl -e 'open my $FH, ">file"; print $FH join "|", stat STDOUT '

---

尝试在

使用

行之后添加

$|=1

：

#!/usr/bin/perl
use warnings;
use strict;

$|=1;

print "Here's some text\n";
print STDERR "Here's some text\n";
print STDOUT "Here's some text\n";

open FH, ">", "file.txt" or die $!;

print FH "Here's some text\n";

strace输出还显示，由于Perl的输出缓冲，打印到文件是在脚本退出时完成的，而不是在脚本运行时完成的

如果

$|=1

无效：请尝试获取脚本使用的FDs：

#!/usr/bin/perl
system "ls -l /proc/$$/fd";

或

---

他们应该给你一个输出应该去哪里的提示。

在开始阅读之前，先看看这个命令的输出。一切都指向了STDOUT指向了错误的地方

ls -l /proc/$$/fd/{1,2}

在我的系统中，我得到了这个，注意，当我写这个的时候，它确实发生了变化，因为这不是一次性写的

lrwx------ 1 root root 64 May  3 17:01 /proc/27806/fd/1 -> /dev/pts/1
lrwx------ 1 root root 64 May  3 17:01 /proc/27806/fd/2 -> /dev/pts/1

我想上述情况对你来说是类似的。对我来说，这个数据看起来很可疑，如果我可以访问文件系统，我会搜索它告诉我它正在写入ie的inode

sudo find / -printf "%i:\t%p\n"|grep 261126

如果Perl启动时将其stdout等更改到错误的位置，我会在脚本中添加很长的睡眠时间，然后进行搜索以查看它在哪里。如果该文件是一个常规文件，并且它位于文件系统上，那么应该可以找到它

我的数据在STDOUT上

|dev   |inode  |mode  |link |uid |gid |rdev |size |atime     |mtime     |ctime     |blk |blka
|13    |3      |8592  |1    |1000|5   |34816|0    |1462301986|1462301986|1462301958|1024|0

|dev   |inode  |mode  |link |uid |gid |rdev |size |atime     |mtime     |ctime     |blk |blka
|45826 |261126 |33188 |1    |1001|1004|0    |0    |1461024408|1461035504|1461035504|4096|0

你的数据在STDOUT上

|dev   |inode  |mode  |link |uid |gid |rdev |size |atime     |mtime     |ctime     |blk |blka
|13    |3      |8592  |1    |1000|5   |34816|0    |1462301986|1462301986|1462301958|1024|0

|dev   |inode  |mode  |link |uid |gid |rdev |size |atime     |mtime     |ctime     |blk |blka
|45826 |261126 |33188 |1    |1001|1004|0    |0    |1461024408|1461035504|1461035504|4096|0

在我的

dev

上有一个小数字13，当我在设备下搜索它时，它看起来还不错。如果我们把你的面具遮住以显示你的大调/小调

major == 179
minor == 2

请注意，我最初是用相反的方式进行的，直到被更正

在我的机器上这是

crw-------  1 root  root   2, 179 Apr 29 12:50 ptya3

我的

rdev

相当于

major == 136 
minor == 0

在我的Debian系统上，这是

/dev/pts/0

。您的

rdev

为0。我快速浏览了一下，一些使用屏幕的人可能会遇到

/dev/pts/N

问题，即屏幕不在那里，但这是我的猜测

strace也很奇怪，当它在我的系统中写入时，我得到了以下几行：

read(3, "#!/usr/bin/perl -w\n#use strict;\n"..., 8192) = 228
read(3, "", 8192)                       = 0
close(3)                                = 0
write(1, "Here's some text STDOUT\n", 24Here's some text STDOUT
) = 24
write(2, "Here's some text STDERR\n", 24Here's some text STDERR
) = 24
write(1, "Here's some text STDOUT\n", 24Here's some text STDOUT
) = 24

事实上，这些东西在你的视线中没有出现，这确实很奇怪。您可以通过使用

$|

来更改显示位置，但它们应该出现在某个位置。注意，模式也很奇怪。如果运行此脚本

#!/usr/bin/perl
use warnings;
use strict;
use Fcntl ':mode';
my $mode = 33188;
my $user_rwx      = ($mode & S_IRWXU) >> 6;
print("user_rwx      = $user_rwx\n");
my $group_read    = ($mode & S_IRGRP) >> 3;
print("group_read    = $group_read\n");
my $other_execute    =  $mode & S_IXOTH;
print("other_execute = $other_execute\n");
printf "Permissions are %04o\n", S_IMODE($mode), "\n";
my $is_setuid     =  $mode & S_ISUID;
print("is_setuid     = $is_setuid\n");
my $is_directory  =  S_ISDIR($mode);
print("dir           = $is_directory\n");
my $is_reg  = S_ISREG($mode);
print("regular       = $is_reg\n");

您可以看到STDOUT似乎指向一个常规文件。这将证实为什么

rdev

为零，也就是说，如果stdout重定向到某个本来是设备但实际上只是普通文件的文件。我曾在chrooted环境中看到过类似的奇怪事情，在这些环境中，设备没有正确设置

---

无论缓冲区在退出时处于打开或关闭状态，缓冲区都应该已刷新（即您将看到对write sys调用的调用）。strace中根本没有写操作，这真的很奇怪。

尝试创建一个新的用户帐户，并使用它来查看是否出现相同的问题，我也会在较新的Perl上尝试，因为我无法在具有5.22的pi上复制它。这看起来很像您的shell中有一些意外的东西，模块安装中断，或者您有一个神秘的提示命令正在吞噬输出

---

strace中缺少对STDOUT和STDERR的写入，这表明它们在该部分代码运行之前以错误的方式打开。

在您提供的信息中有几个有趣的线索：

perl-e'print“foo”或die$！'

给出了一个9的退出代码，即EBADF，这意味着STDOUT指向了一个错误的文件描述符。这可以是任意数字（因为底层文件描述符只是数字），也可以是以前打开但现在关闭的文件描述符。（这也意味着它没有（比如）重定向到/dev/null——这将导致没有输出，但不会给出错误。）

您的

strace

输出显示了几个

open

和

close

调用，它们看起来都是成对的，没有关闭STDOUT的迹象。重要的是，

open

调用all return FD 3（稍后，在FD 3仍在使用的情况下调用FD 4）——在类Unix系统上，

open

通常返回最低未使用的FD，因此这进一步证明了FD 1（通常的STDOUT）在进程启动后没有关闭

这意味着STDOUT并没有连接到fd1，而是与其他一些FD相关联。运行以下命令可以告诉您它是什么：

perl -e 'open my $FH, ">", file.txt"; print $FH fileno(STDOUT)'

我猜这将是一个任意的数字，并且是特定于您在Raspberry Pi上安装的某个问题的结果——可能是某个损坏的库。但是，与之前一样，您可以运行

lsof

来查找进程已打开的FDs（向脚本添加

sleep

以保持其运行），或者查看/proc。但很可能STDOUT指的不是一个开放的FD。有点奇怪的是，您的

strace

输出甚至没有显示对

write

的错误调用；这意味着Perl确实知道FD是无效的

另一个我

perl -le 'open(STDOUT, ">&1"); print "hello"'

perl -MConfig -le 'open my $FH, ">", version.txt"; print Config::myconfig(); print foreach Config::local_patches()'