Environment-Variables
為什麼 uname -M 返回一個空字元串？
在完全相同的機器（AIX 6.1）上，在 2 個不同的登錄 shell（都是 ksh）中，使用不同的使用者 ID，我可以這樣做
uname -M；在一個外殼中，我得到了系統模型。在另一個外殼中，我得到了空白！唯一的區別是使用者 ID 和環境。我不能把環境放在這裡。範例使用者 1 外殼：
$ uname -M IBM,1234-567 $範例使用者 2 外殼：
$ uname -M $我在兩個外殼上都做了一個桁架。有區別，但我不明白。這是壞的桁架：
truss uname -M .. a bunch of execve's ripped out as it was searching the PATH for uname. execve("/bin/uname", 0x2FF2155C, 0x20012EF8) argc: 2 __loadx(0x03480000, 0x2FF21380, 0x00000108, 0xF0713968, 0x20000CD0) = 0x00000000 __loadx(0x0A040000, 0xD042D064, 0x0000008A, 0x20001254, 0x00000000) = 0x00000000 sbrk(0x00000000) = 0x200013D0 vmgetinfo(0x2FF20530, 7, 16) = 0 sbrk(0x00000000) = 0x200013D0 __libc_sbrk(0x00000000) = 0x200013D0 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 __loadx(0x01480080, 0x2FF1FEF0, 0x00000A50, 0x2FF20A60, 0x2FF22ED1) = 0xD0538128 __loadx(0x01480180, 0x2FF1FEF0, 0x00000A50, 0xF068921C, 0xF068914C) = 0xF0759FA0 __loadx(0x07080000, 0xF06891EC, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF3C __loadx(0x07080000, 0xF068912C, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF48 __loadx(0x07080000, 0xF06891FC, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF78 __loadx(0x07080000, 0xF068913C, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF84 __loadx(0x07080000, 0xF06891BC, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF54 __loadx(0x07080000, 0xF068915C, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF6C __loadx(0x07080000, 0xF06891CC, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AF90 __loadx(0x07080000, 0xF06891DC, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AFC0 __loadx(0x07080000, 0xF068916C, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075AFA8 __loadx(0x07080000, 0xF068917C, 0xFFFFFFFF, 0xF0759FA0, 0x00000000) = 0xF075B020 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 __loadx(0x01480080, 0x2FF1FEF0, 0x00000A50, 0x2FF20A60, 0x2FF22ED1) = 0xD0538128 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 __loadx(0x01480080, 0x2FF1FEF0, 0x00000A50, 0x2FF20A60, 0x2FF22ED1) = 0xD0538128 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 __loadx(0x01480080, 0x2FF1FEF0, 0x00000A50, 0x2FF20A60, 0x2FF22ED1) = 0xD0538128 getuidx(4) = 28633 getuidx(2) = 28633 getuidx(1) = 28633 getgidx(4) = 100 getgidx(2) = 100 getgidx(1) = 100 __loadx(0x01480080, 0x2FF1FEF0, 0x00000A50, 0x2FF20A60, 0x2FF22ED1) = 0xD0538128 access("/usr/lib/nls/msg/en_US/uname.cat", 0) = 0 _getpid() = 7405946 uname(0x2000132C) = 0 statx("CuAt", 0x2FF20870, 76, 0) Err#2 ENOENT kopen("CuAt", O_RDONLY) Err#2 ENOENT kioctl(1, 22528, 0x00000000, 0x00000000) = 0 kwrite(1, "\n", 1) = 1 __loadx(0x04000000, 0x2FF20970, 0x00000800, 0x0000D032, 0x00000000) = 0x00000000 kfcntl(1, F_GETFL, 0x00000001) = 67110914 kfcntl(2, F_GETFL, 0x2FF22FFC) = 67110914 _exit(0)你可以看到
kwrite最後只是列印出一個換行符，"\n".在良好的 truss 輸出中，看起來 uname 正在從以下位置獲取屬性：
/etc/objrepos/CuAt這導致我
lsattr指揮和其他人。為什麼 uname -M 為空白？哪些環境變數會影響這一點？
我得到了它。我正在掃描“好”環境並看到了這個環境變數：
export ODMDIR=/etc/objrepos知道“好桁架”在這裡尋找機器型號，我在壞殼中執行了這個命令，現在 uname -M 工作：
$ uname -M IBM,1234-567對不起，我沒有發布環境，但它很大並且包含很多敏感資訊。