Bash缺少所有shell命令

Question

我正试图把男朋友的旧电脑转换成一个开发环境，因为我的电脑坏了，我买不起一台新的电脑，但它似乎失去了我习惯的每一个shell命令。它连ls都没有！

help命令提供了以下内容：

bash-4.4$ help
GNU bash, version 4.4.12(1)-release (x86_64-apple-darwin17.0.0)
These shell commands are defined internally.  Type `help' to see this list.
Type `help name' to find out more about the function `name'.
Use `info bash' to find out more about the shell in general.
Use `man -k' or `info' to find out more about commands not in this list.

A star (*) next to a name means that the command is disabled.

 job_spec [&]                            history [-c] [-d offset] [n] or hist>
 (( expression ))                        if COMMANDS; then COMMANDS; [ elif C>
 . filename [arguments]                  jobs [-lnprs] [jobspec ...] or jobs >
 :                                       kill [-s sigspec | -n signum | -sigs>
 [ arg... ]                              let arg [arg ...]
 [[ expression ]]                        local [option] name[=value] ...
 alias [-p] [name[=value] ... ]          logout [n]
 bg [job_spec ...]                       mapfile [-d delim] [-n count] [-O or>
 bind [-lpsvPSVX] [-m keymap] [-f file>  popd [-n] [+N | -N]
 break [n]                               printf [-v var] format [arguments]
 builtin [shell-builtin [arg ...]]       pushd [-n] [+N | -N | dir]
 caller [expr]                           pwd [-LP]
 case WORD in [PATTERN [| PATTERN]...)>  read [-ers] [-a array] [-d delim] [->
 cd [-L|[-P [-e]] [-@]] [dir]            readarray [-n count] [-O origin] [-s>
 command [-pVv] command [arg ...]        readonly [-aAf] [name[=value] ...] o>
 compgen [-abcdefgjksuv] [-o option] [>  return [n]
 complete [-abcdefgjksuv] [-pr] [-DE] >  select NAME [in WORDS ... ;] do COMM>
 compopt [-o|+o option] [-DE] [name ..>  set [-abefhkmnptuvxBCHP] [-o option->
 continue [n]                            shift [n]
 coproc [NAME] command [redirections]    shopt [-pqsu] [-o] [optname ...]
 declare [-aAfFgilnrtux] [-p] [name[=v>  source filename [arguments]
 dirs [-clpv] [+N] [-N]                  suspend [-f]
 disown [-h] [-ar] [jobspec ... | pid >  test [expr]
 echo [-neE] [arg ...]                   time [-p] pipeline
 enable [-a] [-dnps] [-f filename] [na>  times
 eval [arg ...]                          trap [-lp] [[arg] signal_spec ...]
 exec [-cl] [-a name] [command [argume>  true
 exit [n]                                type [-afptP] name [name ...]
 export [-fn] [name[=value] ...] or ex>  typeset [-aAfFgilnrtux] [-p] name[=v>
 false                                   ulimit [-SHabcdefiklmnpqrstuvxPT] [l>
 fc [-e ename] [-lnr] [first] [last] o>  umask [-p] [-S] [mode]
 fg [job_spec]                           unalias [-a] name [name ...]
 for NAME [in WORDS ... ] ; do COMMAND>  unset [-f] [-v] [-n] [name ...]
 for (( exp1; exp2; exp3 )); do COMMAN>  until COMMANDS; do COMMANDS; done
 function name { COMMANDS ; } or name >  variables - Names and meanings of so>
 getopts optstring name [arg]            wait [-n] [id ...]
 hash [-lr] [-p pathname] [-dt] [name >  while COMMANDS; do COMMANDS; done
 help [-dms] [pattern ...]               { COMMANDS ; }

找.bashrc和.profile在~，我找不到它。我不想破坏整个过程，我从我的旧计算机上得到了一个优化的bash配置文件，但是它显然是假设命令来自几乎所有其他mac命令提示符。有什么好办法让一切都好起来睡觉吗？这只小狗是一个Macbook Pro从2012年年中，但运行高塞拉利昂10.13。

Answer 1

这个纯bash代码不使用外部实用程序(因此应该运行)，并将列出几个标准目录中可用的命令名：

for f in /tmp/num* ; do echo > $f ; done
for f in /bin/* /usr/bin/* /sbin/* /usr/sbin/* ; do \
    test -x "$f" && { n="${f##*/}" ; echo "$n" >> /tmp/num${#n} ; }
done
for f in /tmp/num{1..10} ; do printf %$((${f##*num}+1))s $(<$f) ; done ; echo

输出有点奇怪，(试试！)使用纯bash，没有像sort、column等外部实用程序来提高输出的可读性，而且由于让bash模拟那些实用程序很痛苦，所以我决定将所有一个字母的可执行文件放在一起，然后列出两个字母的可执行文件，然后是三个字母的可执行文件等等，长达10个字母。在任何系统中，通常都有许多名称大于10个字母的实用程序，但是列出的这些功能应该足以使事情变得正确。

为什么要这么做？它让有一个坏掉的$PATH的用户看到一切都不是没有希望的。或者在少数情况下，如果它失败了，那么它就证明了事情确实处于糟糕的状态。

在查看了生成的命令转储之后，假设修复事物所需的实用程序都在那里。下面是一个纯bash函数来获取它们的完整路径名：

findcommand() { printf "%s\n" /bin/* /usr/bin/* /sbin/* /usr/sbin/* |
                while read x ; do 
                   for f in $@ ; do 
                      [ "${x##*/}" = "$f" ] && echo $x
                done ; done ; }

用法，假设我们确实需要sort、column、ls和文本编辑器：

findcommand sort column ls vi jed mcedit 

在我的Lubuntu系统上输出：

/bin/ls
/usr/bin/column
/usr/bin/mcedit
/usr/bin/sort
/usr/bin/vi

注意，由于没有安装jed，所以它没有路径名。