WHICH(1)                                                      General Commands Manual                                                      WHICH(1)



NAME
       which - locate a command

#就是用来找一个命令的绝对路径

SYNOPSIS
       which [-a] filename ...

DESCRIPTION
       which returns the pathnames of the files (or links) which would be executed in the current environment, had its arguments been given as com‐
       mands in a strictly POSIX-conformant shell.  It does this by searching the PATH for executable files matching the names of the arguments. It
       does not follow symbolic links.

OPTIONS
       -a     print all matching pathnames of each argument

EXIT STATUS
       0      if all specified commands are found and executable

       1      if one or more specified commands is nonexistent or not executable

       2      if an invalid option is specified


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WHEREIS(1)                                                         User Commands                                                         WHEREIS(1)



NAME
       whereis - locate the binary, source, and manual page files for a command

#寻找一个命令的绝对路径，源代码，用户手册

SYNOPSIS
       whereis [-bmsu] [-BMS directory...  -f] filename...

DESCRIPTION
       whereis  locates  source/binary  and manuals sections for specified files.  The supplied names are first stripped of leading pathname compo‐
       nents and any (single) trailing extension of the form .ext, for example, .c.  Prefixes of s.  resulting from use of source code control  are
       also dealt with.  whereis then attempts to locate the desired program in a list of standard Linux places.

OPTIONS

       -b     Search only for binaries.
　　　　　　

　　　　　　#相当于 which ls

       -m     Search only for manual sections.

　　　　　　

       -s     Search only for sources.

以下三个选项用来改变相应的搜索路径
       -B     Change or otherwise limit the places where whereis searches for binaries.

       -M     Change or otherwise limit the places where whereis searches for manual sections.

       -S     Change or otherwise limit the places where whereis searches for sources.

       -u     Search  for  unusual  entries.   A  file  is  said  to  be  unusual  if  it  does  not  have  one entry of each requested type.  Thus
              `whereis  -m  -u  *‘ asks for those files in the current directory which have no documentation.

       -f     Terminate the last directory list and signals the start of file names, and must be used when any of the -B, -M,  or  -S  options  are
              used.

EXAMPLE
       Find all files in /usr/bin which are not documented in /usr/man/man1 with source in /usr/src:

              example% cd /usr/bin
              example% whereis -u -M /usr/man/man1 -S /usr/src -f *

FILES
       /{bin,sbin,etc}

       /usr/{lib,bin,old,new,local,games,include,etc,src,man,sbin,
                           X386,TeX,g++-include}

       /usr/local/{X386,TeX,X11,include,lib,man,etc,bin,games,emacs}

SEE ALSO
       chdir(2V)

BUGS
       Since whereis uses chdir(2V) to run faster, pathnames given with the -M, -S, or -B must be full; that is, they must begin with a `/‘.

       whereis has a hard-coded path, so may not always find what you‘re looking for.

AVAILABILITY
       The whereis command is part of the util-linux package and is available from ftp://ftp.kernel.org/pub/linux/utils/util-linux/.



util-linux                                                           July 2009                                                           WHEREIS(1)

Linux -- which whereis