No manual entry for ls解决办法

如果在 Linux 中运行 man ls 命令时提示“no manual entry for ls”，则可能是因为您的系统没有安装 man 页面或者该页面已经被删除。此外，也有可能是您输入的命令不是标准命令。

可以通过以下方式进行排查：

1.确认 man 是否已安装

使用以下命令检查系统中是否已安装 man 命令：

which man

如果命令输出了 man 的路径，则表示 man 命令已经安装在系统中。

2.确认 ls 是否为标准命令

有些自定义的命令可能无法在 man 页面中找到，这是因为它们不是标准命令。使用以下命令确定 ls 是否为标准命令：

type -a ls

如果命令输出了 /bin/ls 或者 /usr/bin/ls，则表示 ls 是标准命令。

3.安装缺失的 man 页面

系统默认安装的 manpage 不够齐全。以 Ubuntu 为例，可以按照如下方式进行安装：

sudo apt install manpages-dev glibc-doc manpages-posix manpages-posix-dev

jetsontx2nx606@jetsontx2nx606-desktop:~$ sudo apt install manpages-dev glibc-doc manpages-posix manpages-posix-dev
Reading package lists... Done
Building dependency tree       
Reading state information... Done
manpages-dev is already the newest version (4.15-1).
manpages-dev set to manually installed.
The following packages were automatically installed and are no longer required:
  activity-log-manager libgeonames-common libgeonames0 libnm-gtk0 libpinyin-data libpinyin13
  libtimezonemap-data libtimezonemap1 libunity-control-center1
Use 'sudo apt autoremove' to remove them.
The following NEW packages will be installed:
  glibc-doc glibc-doc-reference manpages-posix manpages-posix-dev
0 upgraded, 4 newly installed, 0 to remove and 197 not upgraded.
Need to get 8,228 kB of archives.
After this operation, 19.6 MB of additional disk space will be used.
Get:1 http://ports.ubuntu.com/ubuntu-ports bionic/multiverse arm64 manpages-posix all 2013a-2 [929 kB]
Get:2 http://ports.ubuntu.com/ubuntu-ports bionic/multiverse arm64 manpages-posix-dev all 2013a-2 [1,794 kB]
Get:3 http://ports.ubuntu.com/ubuntu-ports bionic/main arm64 glibc-doc-reference all 2.27-1 [5,483 kB]
Get:4 http://ports.ubuntu.com/ubuntu-ports bionic-updates/main arm64 glibc-doc all 2.27-3ubuntu1.6 [22.2 kB]
Fetched 8,228 kB in 7s (1,232 kB/s)                                                           
debconf: delaying package configuration, since apt-utils is not installed
Selecting previously unselected package manpages-posix.
(Reading database ... 192285 files and directories currently installed.)
Preparing to unpack .../manpages-posix_2013a-2_all.deb ...
Unpacking manpages-posix (2013a-2) ...
Selecting previously unselected package manpages-posix-dev.
Preparing to unpack .../manpages-posix-dev_2013a-2_all.deb ...
Unpacking manpages-posix-dev (2013a-2) ...
Selecting previously unselected package glibc-doc-reference.
Preparing to unpack .../glibc-doc-reference_2.27-1_all.deb ...
Unpacking glibc-doc-reference (2.27-1) ...
Selecting previously unselected package glibc-doc.
Preparing to unpack .../glibc-doc_2.27-3ubuntu1.6_all.deb ...
Unpacking glibc-doc (2.27-3ubuntu1.6) ...
Setting up glibc-doc-reference (2.27-1) ...
Setting up glibc-doc (2.27-3ubuntu1.6) ...
Setting up manpages-posix (2013a-2) ...
Setting up manpages-posix-dev (2013a-2) ...
Processing triggers for man-db (2.8.3-2ubuntu0.1) ...

4.如果仍然无法运行，则需要手动安装man手册页

4.1.首先从官网链接下载最新版的man手册源码包

wget https://mirrors.edge.kernel.org/pub/linux/docs/man-pages/man-pages-6.03.tar.gz

4.2.解压源码包

tar -xzvf man-pages-6.03.tar.gz

4.3.安装man手册

#进入目标目录
cd man-pages-6.03/
#切换到root用户
su
#安装
make install

这样就能正常运行了。