8. strip

strip [‘-F’ bfdname |‘--target=’bfdname]
      [‘-I’ bfdname |‘--input-target=’bfdname]
      [‘-O’ bfdname |‘--output-target=’bfdname]
      [‘-s’|‘--strip-all’]
      [‘-S’|‘-g’|‘-d’|‘--strip-debug’]
      [‘-K’ symbolname |‘--keep-symbol=’symbolname]
      [‘-N’ symbolname |‘--strip-symbol=’symbolname]
      [‘-w’|‘--wildcard’]
      [‘-x’|‘--discard-all’] [‘-X’ |‘--discard-locals’]
      [‘-R’ sectionname |‘--remove-section=’sectionname]
      [‘-o’ file] [‘-p’|‘--preserve-dates’]
      [‘--keep-file-symbols’]
      [‘--only-keep-debug’]
      [‘-v’ |‘--verbose’] [‘-V’|‘--version’]
      [‘--help’] [‘--info’]
      objfile…

GNU strip discards all symbols from object files objfile. The list of object files may include archives. At least one object file must be given.

strip modifies the files named in its argument, rather than writing modified copies under different names.

-F bfdname

--target=bfdname

Treat the original objfile as a file with the object code format bfdname, and rewrite it in the same format. See section Target Selection, for more information.

--help

Show a summary of the options to strip and exit.

--info

Display a list showing all architectures and object formats available.

-I bfdname

--input-target=bfdname

Treat the original objfile as a file with the object code format bfdname. See section Target Selection, for more information.

-O bfdname

--output-target=bfdname

Replace objfile with a file in the output format bfdname. See section Target Selection, for more information.

-R sectionname

--remove-section=sectionname

Remove any section named sectionname from the output file. This option may be given more than once. Note that using this option inappropriately may make the output file unusable.

-s

--strip-all

Remove all symbols.

-g

-S

-d

--strip-debug

Remove debugging symbols only.

--strip-unneeded

Remove all symbols that are not needed for relocation processing.

-K symbolname

--keep-symbol=symbolname

When stripping symbols, keep symbol symbolname even if it would normally be stripped. This option may be given more than once.

-N symbolname

--strip-symbol=symbolname

Remove symbol symbolname from the source file. This option may be given more than once, and may be combined with strip options other than ‘-K’.

-o file

Put the stripped output in file, rather than replacing the existing file. When this argument is used, only one objfile argument may be specified.

-p

--preserve-dates

Preserve the access and modification dates of the file.

-w

--wildcard

Permit regular expressions in symbolnames used in other command line options. The question mark (?), asterisk (*), backslash (\) and square brackets ([]) operators can be used anywhere in the symbol name. If the first character of the symbol name is the exclamation point (!) then the sense of the switch is reversed for that symbol. For example:

-w -K !foo -K fo*

would cause strip to only keep symbols that start with the letters “fo”, but to discard the symbol “foo”.

-x

--discard-all

Remove non-global symbols.

-X

--discard-locals

Remove compiler-generated local symbols. (These usually start with ‘L’ or ‘.’.)

--keep-file-symbols

When stripping a file, perhaps with ‘--strip-debug’ or ‘--strip-unneeded’, retain any symbols specifying source file names, which would otherwise get stripped.

--only-keep-debug

Strip a file, removing contents of any sections that would not be stripped by ‘--strip-debug’ and leaving the debugging sections intact. In ELF files, this preserves all note sections in the output.

The intention is that this option will be used in conjunction with ‘--add-gnu-debuglink’ to create a two part executable. One a stripped binary which will occupy less space in RAM and in a distribution and the second a debugging information file which is only needed if debugging abilities are required. The suggested procedure to create these files is as follows:

1. Link the executable as normal. Assuming that is is called foo then...
2. Run objcopy --only-keep-debug foo foo.dbg to create a file containing the debugging info.
3. Run objcopy --strip-debug foo to create a stripped executable.
4. Run objcopy --add-gnu-debuglink=foo.dbg foo to add a link to the debugging info into the stripped executable.

Note - the choice of .dbg as an extension for the debug info file is arbitrary. Also the --only-keep-debug step is optional. You could instead do this:

1. Link the executable as normal.
2. Copy foo to foo.full
3. Run strip --strip-debug foo
4. Run objcopy --add-gnu-debuglink=foo.full foo

ie the file pointed to by the ‘--add-gnu-debuglink’ can be the full executable. It does not have to be a file created by the ‘--only-keep-debug’ switch.

Note - this switch is only intended for use on fully linked files. It does not make sense to use it on object files where the debugging information may be incomplete. Besides the gnu_debuglink feature currently only supports the presence of one filename containing debugging information, not multiple filenames on a one-per-object-file basis.

-V

--version

Show the version number for strip.

-v

--verbose

Verbose output: list all object files modified. In the case of archives, ‘strip -v’ lists all members of the archive.