user1032531's questions

尝试配置 PHP 以执行核心转储，我执行了以下操作：

[root@myserver ~]# echo '/tmp/core-%e.%p' > /proc/sys/kernel/core_pattern
[root@myserver ~]# echo 0 > /proc/sys/kernel/core_uses_pid
[root@myserver ~]# ulimit -c unlimited

我不知道原来的 ulimit 值是什么，但它们现在如下：

[michael@myserver ~]$ ulimit
unlimited
[michael@myserver ~]$ ulimit -a
core file size          (blocks, -c) 0
data seg size           (kbytes, -d) unlimited
scheduling priority             (-e) 0
file size               (blocks, -f) unlimited
pending signals                 (-i) 7867
max locked memory       (kbytes, -l) 64
max memory size         (kbytes, -m) unlimited
open files                      (-n) 1024
pipe size            (512 bytes, -p) 8
POSIX message queues     (bytes, -q) 819200
real-time priority              (-r) 0
stack size              (kbytes, -s) 8192
cpu time               (seconds, -t) unlimited
max user processes              (-u) 4096
virtual memory          (kbytes, -v) unlimited
file locks                      (-x) unlimited
[michael@myserver ~]$

我还对 php-fpm 配置文件进行了一些更改，但已经将它们改回了默认设置。

我正在运行 Centos7。我应该将 ulimit 值设置回什么？另外，我应该做些什么来反转这两个echo命令吗？

我有一个 PHP 应用程序，它位于 Linux 上，有多个目录（和子目录）和许多 PHP、JS、HTML、CSS 等文件。许多文件都有 Windows EOL 控制字符，我还担心有些文件可能不是 UTF-8 编码，但可能是 ISO-8859-1、Windows-1252 等。我希望使用 LF 将所有文件转换为 UTF-8只要。

看起来我可能有几个步骤。

dos2unix man 提供了这个解决方案：

find . -name *.txt |xargs dos2unix

https://stackoverflow.com/a/11929475提供了这个解决方案：

find . -type f -print0 | xargs -0 dos2unix

https://stackoverflow.com/a/7068241提供了这个解决方案：

find ./ -type f -exec dos2unix {} \;

我认识到第一个只会转换不是我想要的 txt 文件，但我可以轻松更改为使用-type f. 话虽如此，一种解决方案是否比另一种解决方案“更好”？如果是这样，为什么？是否可以在不更改文件的情况下判断哪些文件将被更改？当我最终更改它们时，我不想更改日期，并打算使用 dos2unix 的--keepdate标志。是否应该使用任何其他选项？

接下来，我需要处理编码。 https://stackoverflow.com/a/805474/1032531推荐enca（或其姊妹命令encov）和https://stackoverflow.com/a/64889/1032531推荐iconv。它似乎也file可能适用。同样，应该使用哪一个（或者可能是其他所有东西）？我安装enca并执行时enca --list languages，它列出了几种语言，但没有列出英语（也许选择“无”？），我的问题是适用性。 iconv已经安装了，但是，它没有手册页（至少man iconv没有手册页）。这如何用于递归检查和转换编码？

请确认/更正我提出的解决方案或提供完整的解决方案。

我之前使用 yum 在 Centos7 上安装了 git 版本 1.8.3.1。我现在想要一个更新版本的 git。需要先删除 yum 包吗？

-n用作显示行号的 grep 参数，但-H不适用于文件名。我认为这是因为git diff默认情况下不会为每个更改的行输出文件名。当我打字时，我考虑了另一种显示多行的选项，它解决了我的直接问题，但仍然想知道显示实际文件名的解决方案。

[michael@bigbox www]$ git diff | grep -n -H "this->config"
(standard input):614:-        $config=json_decode($this->config,true);
[michael@bigbox www]$

执行后apt-key list，我看到一个我希望删除的密钥。

...
pub   rsa2048 2017-11-24 [SC]
      3241 413F 3CE0 B919 E82F  DCA0 6239 92CF C9A9 7C2C
uid           [ unknown] John Doe <[email protected]>
sub   rsa2048 2017-11-24 [E]
...

man apt-key告诉我可以通过执行删除密钥apt-key del keyid。它还告诉我list(aka finger) 将列出带有指纹的受信任密钥，所以我假设这3241 413F 3CE0 B919 E82F DCA0 6239 92CF C9A9 7C2C是指纹而不是 keyid。我弄乱了gpg --list-keysand gpg --list-public-keys，但是，它没有列出任何键，而是~/.gnupg/使用不显示键 ID 的各种非文本文件创建。

如何识别 keyid 以便我可以删除密钥？

PS。在问这个问题之前，我搜索了一个解决方案，有些人建议不要使用“short key ids”。如果我不应该按照 描述的 keyid 删除密钥man apt-key，请提供适当的方式。

我最近在多台机器上使用dd. 我的命名还没有完成出色的工作，并且有一些重复。如何快速确定两个图像是否相等？我一直在使用diff，但需要一段时间。

我希望永久安装以下挂载：

[michael@devserver ~]$ findmnt | grep public
└─/home/jail/home/public/repo         /dev/mapper/centos-root[/home/michael/testing/gateway/repo] xfs        ro,relatime,attr2,inode64,noquota
[michael@devserver ~]$

我使用以下内容创建了这个安装：

sudo mkdir /home/jail/home/public/repo
sudo mount --bind /home/michael/testing/gateway/repo /home/jail/home/public/repo
sudo mount -o remount,ro,bind /home/jail/home/public/repo

我/etc/fstab目前的样子如下。我希望我应该只添加/home/michael/testing/gateway/repo /home/jail/home/public/repo xfs ro,relatime,attr2,inode64,noquota 0 0到/etc/fstab，但是这样做后，我的服务器阻塞，我必须进入紧急模式才能从/etc/fstab. 永久绑定挂载目录以进行只读访问的正确方法是什么？

[michael@devserver ~]$ cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri Apr  8 14:15:42 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        1 1
UUID=362355d4-e5da-44de-bf5c-5ce92cf43888 /boot                   xfs     defaults        1 2
/dev/mapper/centos-swap swap                    swap    defaults        0 0

[michael@devserver ~]$

我刚刚安装了一些软件apt-get，它的所有者和组是“logger”。既然我使用 安装了软件sudo，为什么所有者和组不是“root”？我很确定大约一年前，我pi用新名称重命名了用户logger。这可能导致它，如果是这样，为什么？

michael@rp3:~ $ ls -l /usr | grep local
drwxrwsr-x  12 root staff  4096 Dec 23 16:49 local
michael@rp3:~ $ ls -l /usr/local
total 32
drwxrwsr-x 2 root staff 4096 Dec 23 16:47 bin
drwxrwsr-x 2 root staff 4096 Apr 10  2017 etc
drwxrwsr-x 2 root staff 4096 Apr 10  2017 games
drwxrwsr-x 2 root staff 4096 Apr 10  2017 include
drwxrwsr-x 4 root staff 4096 Jun  4  2017 lib
lrwxrwxrwx 1 root staff    9 Apr 10  2017 man -> share/man
drwxrwsr-x 2 root staff 4096 Apr 10  2017 sbin
drwxrwsr-x 7 root staff 4096 Dec 23 15:20 share
drwxrwsr-x 2 root staff 4096 Apr 10  2017 src
michael@rp3:~ $ sudo apt-get install test-client
Reading package lists... Done
Building dependency tree
Reading state information... Done
The following additional packages will be installed:
  test-utils
The following NEW packages will be installed:
  test-client test-utils
0 upgraded, 2 newly installed, 0 to remove and 0 not upgraded.
Need to get 0 B/1,575 kB of archives.
After this operation, 0 B of additional disk space will be used.
Do you want to continue? [Y/n] y
WARNING: The following packages cannot be authenticated!
  test-utils test-client
Install these packages without verification? [y/N] y
Selecting previously unselected package test-utils.
(Reading database ... 41030 files and directories currently installed.)
Preparing to unpack .../test-utils_0.1.1-jessie_armhf.deb ...
Unpacking test-utils (0.1.1-jessie) ...
Selecting previously unselected package test-client.
Preparing to unpack .../test-client_0.1.2-jessie_armhf.deb ...
Unpacking test-client (0.1.2-jessie) ...
Setting up test-utils (0.1.1-jessie) ...
Setting up test-client (0.1.2-jessie) ...
michael@rp3:~ $ ls -l /usr/local
total 40
drwxrwxr-x 6 logger logger 4096 Dec 23 16:49 test-client
drwxrwxr-x 3 logger logger 4096 Dec 23 16:49 test-utils
drwxrwsr-x 2 root   staff  4096 Dec 23 16:49 bin
drwxrwsr-x 2 root   staff  4096 Apr 10  2017 etc
drwxrwsr-x 2 root   staff  4096 Apr 10  2017 games
drwxrwsr-x 2 root   staff  4096 Apr 10  2017 include
drwxrwsr-x 4 root   staff  4096 Jun  4  2017 lib
lrwxrwxrwx 1 root   staff     9 Apr 10  2017 man -> share/man
drwxrwsr-x 2 root   staff  4096 Apr 10  2017 sbin
drwxrwsr-x 7 root   staff  4096 Dec 23 15:20 share
drwxrwsr-x 2 root   staff  4096 Apr 10  2017 src

michael@rp3:~ $ cat /etc/passwd | grep 'apt\|logger\|root\|michael'
root:x:0:0:root:/root:/bin/bash
michael:x:1001:1001:,,,:/home/michael:/bin/bash
_apt:x:109:65534::/nonexistent:/bin/false
logger:x:1000:1000:,,,:/home/logger:/bin/bash
michael@rp3:~ $ cat /etc/group | grep 'apt\|logger\|root\|michael'
root:x:0:
michael:x:1001:
wireshark:x:114:michael
logger:x:1000:
michael@rp3:~ $ sudo cat /etc/sudoers
#
# This file MUST be edited with the 'visudo' command as root.
#
# Please consider adding local content in /etc/sudoers.d/ instead of
# directly modifying this file.
#
# See the man page for details on how to write a sudoers file.
#
Defaults        env_reset
Defaults        mail_badpass
Defaults        secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

# Host alias specification

# User alias specification

# Cmnd alias specification

# User privilege specification
root    ALL=(ALL:ALL) ALL
michael  ALL=(ALL:ALL) ALL
anton   ALL=(ALL:ALL) ALL

# Allow members of group sudo to execute any command
%sudo   ALL=(ALL:ALL) ALL

# See sudoers(5) for more information on "#include" directives:

#includedir /etc/sudoers.d
michael@rp3:~ $ ls -l /etc/sudoers.d
total 8
-r--r----- 1 root root  27 Oct 18  2016 010_pi-nopasswd
-r--r----- 1 root root 958 Jan 11  2016 README
michael@rp3:~ $ sudo cat /etc/sudoers.d/*
pi ALL=(ALL) NOPASSWD: ALL
#
# As of Debian version 1.7.2p1-1, the default /etc/sudoers file created on
# installation of the package now includes the directive:
#
#       #includedir /etc/sudoers.d
#
# This will cause sudo to read and parse any files in the /etc/sudoers.d
# directory that do not end in '~' or contain a '.' character.
#
# Note that there must be at least one file in the sudoers.d directory (this
# one will do), and all files in this directory should be mode 0440.
#
# Note also, that because sudoers contents can vary widely, no attempt is
# made to add this directive to existing sudoers files on upgrade.  Feel free
# to add the above directive to the end of your /etc/sudoers file to enable
# this functionality for existing installations if you wish!
#
# Finally, please note that using the visudo command is the recommended way
# to update sudoers content, since it protects against many failure modes.
# See the man page for visudo for more information.
#
michael@rp3:~ $

我成功地将一个目录挂载到另一个路径：

[michael@vps ~]$ mkdir /home/michael/devicefilexxx
[michael@vps ~]$ mkdir /home/michael/mountpointxxx
[michael@vps ~]$ sudo mount --bind /home/michael/devicefilexxx /home/michael/mountpointxxx

我看看它的样子：

[michael@vps ~]$ cat /etc/mtab | grep xxx
/dev/mapper/centos-root /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

好吧，挂载点看起来是正确的，但不是设备。我将设备指定为/home/michael/devicefilexxx，而不是/dev/mapper/centos-root。所以我看的更深一点：

[michael@vps ~]$ mount
sysfs on /sys type sysfs (rw,nosuid,nodev,noexec,relatime)
proc on /proc type proc (rw,nosuid,nodev,noexec,relatime)
devtmpfs on /dev type devtmpfs (rw,nosuid,size=1009596k,nr_inodes=252399,mode=755)
securityfs on /sys/kernel/security type securityfs (rw,nosuid,nodev,noexec,relatime)
tmpfs on /dev/shm type tmpfs (rw,nosuid,nodev)
devpts on /dev/pts type devpts (rw,nosuid,noexec,relatime,gid=5,mode=620,ptmxmode=000)
tmpfs on /run type tmpfs (rw,nosuid,nodev,mode=755)
tmpfs on /sys/fs/cgroup type tmpfs (ro,nosuid,nodev,noexec,mode=755)
cgroup on /sys/fs/cgroup/systemd type cgroup (rw,nosuid,nodev,noexec,relatime,xattr,release_agent=/usr/lib/systemd/systemd-cgroups-agent,name=systemd)
pstore on /sys/fs/pstore type pstore (rw,nosuid,nodev,noexec,relatime)
cgroup on /sys/fs/cgroup/pids type cgroup (rw,nosuid,nodev,noexec,relatime,pids)
cgroup on /sys/fs/cgroup/net_cls,net_prio type cgroup (rw,nosuid,nodev,noexec,relatime,net_prio,net_cls)
cgroup on /sys/fs/cgroup/cpu,cpuacct type cgroup (rw,nosuid,nodev,noexec,relatime,cpuacct,cpu)
cgroup on /sys/fs/cgroup/perf_event type cgroup (rw,nosuid,nodev,noexec,relatime,perf_event)
cgroup on /sys/fs/cgroup/devices type cgroup (rw,nosuid,nodev,noexec,relatime,devices)
cgroup on /sys/fs/cgroup/blkio type cgroup (rw,nosuid,nodev,noexec,relatime,blkio)
cgroup on /sys/fs/cgroup/cpuset type cgroup (rw,nosuid,nodev,noexec,relatime,cpuset)
cgroup on /sys/fs/cgroup/memory type cgroup (rw,nosuid,nodev,noexec,relatime,memory)
cgroup on /sys/fs/cgroup/freezer type cgroup (rw,nosuid,nodev,noexec,relatime,freezer)
cgroup on /sys/fs/cgroup/hugetlb type cgroup (rw,nosuid,nodev,noexec,relatime,hugetlb)
configfs on /sys/kernel/config type configfs (rw,relatime)
/dev/mapper/centos-root on / type xfs (rw,relatime,attr2,inode64,noquota)
systemd-1 on /proc/sys/fs/binfmt_misc type autofs (rw,relatime,fd=34,pgrp=1,timeout=300,minproto=5,maxproto=5,direct)
mqueue on /dev/mqueue type mqueue (rw,relatime)
hugetlbfs on /dev/hugepages type hugetlbfs (rw,relatime)
debugfs on /sys/kernel/debug type debugfs (rw,relatime)
/dev/sda1 on /boot type xfs (rw,relatime,attr2,inode64,noquota)
tmpfs on /run/user/1000 type tmpfs (rw,nosuid,nodev,relatime,size=204060k,mode=700,uid=1000,gid=1000)
/dev/mapper/centos-root on /home/michael/mountpointxxx type xfs (rw,relatime,attr2,inode64,noquota)

嗯，两个设备在同一个挂载点？所以，我看看我的/etc/fstab：

[michael@vps ~]$ cat /etc/fstab

#
# /etc/fstab
# Created by anaconda on Fri Apr  8 14:15:42 2016
#
# Accessible filesystems, by reference, are maintained under '/dev/disk'
# See man pages fstab(5), findfs(8), mount(8) and/or blkid(8) for more info
#
/dev/mapper/centos-root /                       xfs     defaults        1 1
UUID=362355d4-e5da-44de-bf5c-5ce92cf43888 /boot                   xfs     defaults        1 2
/dev/mapper/centos-swap swap                    swap    defaults        0 0

如果我希望在机器重新启动后保持挂载，当然我不想将以下内容添加到/etc/stab：

/dev/mapper/centos-root /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

也许如下，但我犹豫这样做，因为它与/etc/mtab告诉我的不同：

/home/michael/devicefilexxx /home/michael/mountpointxxx xfs rw,relatime,attr2,inode64,noquota 0 0

如何永久挂载目录/文件？另外，请解释如何/dev/mapper/centos-root有两个明显不同的安装点，因此必须安装到不同的设备上。

编辑。备份信息：

[michael@vps ~]$ lsblk
NAME            MAJ:MIN RM  SIZE RO TYPE MOUNTPOINT
sda               8:0    0   80G  0 disk
├─sda1            8:1    0  500M  0 part /boot
└─sda2            8:2    0 79.5G  0 part
  ├─centos-swap 253:0    0    2G  0 lvm  [SWAP]
  └─centos-root 253:1    0 77.5G  0 lvm  /
sr0              11:0    1 1024M  0 rom
[michael@lsblk ~]$

如何在树莓派上安装 systemd-journal-gatewayd？ https://www.freedesktop.org/software/systemd/man/systemd-journal-gatewayd.service.html

拉紧

michael@stetch:~ $ sudo apt-get install systemd-journal-gatewayd
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd
michael@stetch:~ $ sudo apt-get install systemd-journal-gatewayd.socket
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd.socket
E: Couldn't find any package by glob 'systemd-journal-gatewayd.socket'
E: Couldn't find any package by regex 'systemd-journal-gatewayd.socket'
michael@stetch:~ $ sudo apt-get install systemd-journal-gatewayd.service
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd.service
E: Couldn't find any package by glob 'systemd-journal-gatewayd.service'
E: Couldn't find any package by regex 'systemd-journal-gatewayd.service'
michael@stetch:~ $

杰西

michael@jessie:~ $ sudo apt-get install systemd-journal-gatewayd
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd
michael@jessie:~ $ sudo apt-get install systemd-journal-gatewayd.socket
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd.socket
E: Couldn't find any package by regex 'systemd-journal-gatewayd.socket'
michael@jessie:~ $ sudo apt-get install systemd-journal-gatewayd.service
Reading package lists... Done
Building dependency tree
Reading state information... Done
E: Unable to locate package systemd-journal-gatewayd.service
E: Couldn't find any package by regex 'systemd-journal-gatewayd.service'
michael@jessie:~ $

例如，假设（或实际上）有人正在使用并需要继续使用 Debian Jessie，但想使用 Debian Stretch 的 PHP7。他们可能会编辑/etc/apt/sources.list以使用 Stretch 并安装新软件，然后恢复/etc/apt/sources.list为 Jessie。但是他们是否也需要对 nginx 或其他软件包做同样的事情？如果是这样，他们怎么知道？他们是否希望apt-get update在配置为使用 Stretch 期间执行？

我更改了主机名并使其保持不变，但我之前的解决方案不起作用。我正在使用 Linux raspberrypi 4.9.59-v7+ #1047 SMP Sun Oct 29 12:19:23 GMT 2017 armv7l GNU/L。有没有新的方法可以做到这一点（除了重启）？

pi@raspberrypi:~ $ /etc/init.d/hostname.sh
-bash: /etc/init.d/hostname.sh: No such file or directory
pi@raspberrypi:~ $