这是因为当pipe文件的最后一个writer关闭之后,就会自动发送一个EOF。而echo 111 > p完成之后,p就没有writer了,因此会自动发送一个EOF。 因此如果要让echo 111 > p之后不要发送EOF,只需要保持pipe文件至少有一个writer。我们可以在一开始就exec 3>p,把shell的3号file descriptor重定向到pipe文件,这样它就一直有...
would mean character 0 is binary, 1, 2 and 3 are control, 4, 5, 6 and 7 are binary, and 8 is normal. All characters after the last are taken to be the same as the last, so characters 9 through 255 would be normal. (This is an example, and does not necessarily represent any ...
%wheelALL=(ALL)ALL可禁止wheel组内用户的sudo权限。 __EOF__
Firstly the init or the systemd which is the pid 1 process is what controls the runlevel of the system and it determines which processes are launched and running in that runlevel The init is a powerful command which executes the runlevel it is told to. Here the init 0 proceeds to Power...
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It is one of several closely related successors to Greenwich Mean Time (GMT). For most purposes, UTC is synonymous with GMT, but GMT is no longer precisely defined by the scientific ...
We do not know if interrupts were enabled in the mean time. # tracer: preemptoff # preemptoff latency trace v1.1.5 on 2.6.26-rc8 --- latency: 63 us, #87/87, CPU#0 | (M:preempt VP:0, KP:0, SP:0 HP:0 #P:2) --- | task: sshd-4261 (uid:0 nice:0 policy:0 rt_prio:...
bash - What does <<< mean? - Unix & Linux Stack Exchange What is Redirection? Output Redirection Input redirection File Descriptors (FD) Error Redirection Why Error Redirection? sheet Redirection Commands Following is a complete list of commands which you can use for redirection − ...
The man page for each command should indicate the various exit codes and what they mean. Additionally, the builtin commands return exit codes, as does an executed shell function. If a command consists entirely of variable assignments then the exit status of the command is that of the last ...
I mean, after running the script, I needed to press Enter or typeCtrl+C/Ctrl+D, and I would like to have the script terminated after the run. the lines I’ve entered in my script are: echo `cat | ls -ltr > temp3_mask_000` ...
ignore blocks of zeros in archive (normally mean EOF) --ignore-case ignore case when excluding files --ignore-failed-read don’t exit with non-zero status on unreadable files --index-file FILE send verbose output to FILE instead of stdout ...