Путеводитель по Руководству Linux

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   sh.1p    ( 1 )

оболочка, стандартный интерпретатор командного языка (shell, the standard command language interpreter)

Использование в приложениях (Application usage)

Standard input and standard error are the files that determine
       whether a shell is interactive when -i is not specified. For
       example:

sh > file

and:

sh 2> file

create interactive and non-interactive shells, respectively. Although both accept terminal input, the results of error conditions are different, as described in Section 2.8.1, Consequences of Shell Errors; in the second example a redirection error encountered by a special built-in utility aborts the shell.

A conforming application must protect its first operand, if it starts with a <plus-sign>, by preceding it with the "--" argument that denotes the end of the options.

Applications should note that the standard PATH to the shell cannot be assumed to be either /bin/sh or /usr/bin/sh, and should be determined by interrogation of the PATH returned by getconf PATH, ensuring that the returned pathname is an absolute pathname and not a shell built-in.

For example, to determine the location of the standard sh utility:

command -v sh

On some implementations this might return:

/usr/xpg4/bin/sh

Furthermore, on systems that support executable scripts (the "#!" construct), it is recommended that applications using executable scripts install them using getconf PATH to determine the shell pathname and update the "#!" script appropriately as it is being installed (for example, with sed). For example:

# # Installation time script to install correct POSIX shell pathname # # Get list of paths to check # Sifs=$IFS Sifs_set=${IFS+y} IFS=: set -- $(getconf PATH) if [ "$Sifs_set" = y ] then IFS=$Sifs else unset IFS fi # # Check each path for 'sh' # for i do if [ -x "${i}"/sh ] then Pshell=${i}/sh fi done # # This is the list of scripts to update. They should be of the # form '${name}.source' and will be transformed to '${name}'. # Each script should begin: # # #!INSTALLSHELLPATH # scripts="a b c" # # Transform each script # for i in ${scripts} do sed -e "s|INSTALLSHELLPATH|${Pshell}|" < ${i}.source > ${i} done