我尝试运行以下 bash 脚本：
#!/bin/bash
x=1
while [ $x -le 10 ]
do
echo "Welcome $x times"
x = $(( $x + 1))
done
当我运行它时，我会收到一串消息，这些消息似乎会重复，直到我按下 Ctrl-Z 为止。
im4t:test math4tots$ ./mdtest.sh
Welcome 1 times
launch_msg("CheckIn") IPC failure: Operation not permitted
Xquartz: Unable to locate waiting server: org.x.X11
Xquartz: X11.app = /Applications/Utilities/X11.app/Contents/MacOS/X11
Xquartz: Starting X server: /Applications/Utilities/X11.app/Contents/MacOS/X11 --listenonly
X11.app: main(): argc=2
argv[0] = /Applications/Utilities/X11.app/Contents/MacOS/X11.bin
argv[1] = --listenonly
Waiting for startup parameters via Mach IPC.
X11.app: No launchd socket handed off, unsetting DISPLAY
X11.app: do_start_x11_server(): argc=3
argv[0] = x
argv[1] = =
argv[2] = 2
Unrecognized option: =
use: X [:<display>] [option]
-a # default pointer acceleration (factor)
-ac disable access control restrictions
-audit int set audit trail level
-auth file select authorization file
-br create root window with black background
+bs enable any backing store support
-bs disable any backing store support
-c turns off key-click
c # key-click volume (0-100)
...超过 30000 个字符的冗长错误消息...
ttyxx server started from init on /dev/ttyxx
v video blanking for screen-saver
-v screen-saver without video blanking
-wm WhenMapped default backing-store
-wr create root window with white background
-maxbigreqsize set maximal bigrequest size
+xinerama Enable XINERAMA extension
-xinerama Disable XINERAMA extension
-dumbSched Disable smart scheduling, enable old behavior
-schedInterval int Set scheduler interval in msec
-sigstop Enable SIGSTOP based startup
+extension name Enable extension
-extension name Disable extension
-query host-name contact named host for XDMCP
-broadcast broadcast for XDMCP
-multicast [addr [hops]] IPv6 multicast for XDMCP
-indirect host-name contact named host for indirect XDMCP
-port port-num UDP port number to send messages to
-from local-address specify the local address to connect from
-once Terminate server after one session
-class display-class specify display class to send in manage
-cookie xdm-auth-bits specify the magic cookie for XDMCP
-displayID display-id manufacturer display ID for request
[+-]accessx [ timeout [ timeout_mask [ feedback [ options_mask] ] ] ]
enable/disable accessx key sequences
-ardelay set XKB autorepeat delay
-arinterval set XKB autorepeat interval
Device Dependent Usage:
-depth <8,15,24> : use this bit depth.
-fakebuttons : fake a three button mouse with Command and Option keys.
-nofakebuttons : don't fake a three button mouse.
-fakemouse2 <modifiers> : fake middle mouse button with modifier keys.
-fakemouse3 <modifiers> : fake right mouse button with modifier keys.
ex: -fakemouse2 "option,shift" = option-shift-click is middle button.
-version : show the server version.
Fatal server error:
Unrecognized option: (null)
OsVendorFatalError
AbortDDX
^Z
[1]+ Stopped ./mdtest.sh
我还得到一个闪烁的窗口（反复关闭和打开）：
另外，如果它是相关的，我正在使用 Mac OS X Lion，但它似乎并不重要......
它看起来像是一个无害的 bash 脚本......
答案1
此行中有一个额外的空格：
x = $(( $x + 1))
shell 正在尝试运行该程序x，该程序似乎是一个 X 服务器（Mac OS 的标准文件系统不区分大小写，因此我想它实际上正在运行X）。你需要这样做：
x=$(( $x + 1))