24.13 Save Space in Executable Files with strip

Warning!	After you compile ( 52.8 ) and debug a program, there's a part of the executable binary that you can delete to save disk space. The strip command does the job. Note that once you strip a file, you can't use a symbolic debugger like dbx on it!

Here's an example. I'll compile a C program and list it. Then I'll strip it and list it again. How much space you save depends on several factors, but you'll almost always save something.

-s	% cc -o echoerr echoerr.c % ls -ls echoerr 52 -rwxr-xr-x 1 jerry 24706 Nov 18 15:49 echoerr % strip echoerr % ls -ls echoerr 36 -rwxr-xr-x 1 jerry 16656 Nov 18 15:49 echoerr

If you know that you want a file stripped when you compile it, use cc with its -s option. If you use ld -say, in a makefile ( 28.13 ) - use the -s option there.

Here's a shell script named stripper that finds all the unstripped executable files in your bin directory ( 4.2 ) and strips them. It's a quick way to save space on your account. (The same script, searching the whole filesystem, will save even more space for system administrators - but watch out for unusual filenames ( 9.22 ) ):

xargs	#! /bin/sh skipug="! -perm -4000 ! -perm -2000" # SKIP SETUID, SETGID FILES find $HOME/bin -type f \( -perm -0100 $skipug \) -print | xargs file | sed -n '/executable .*not stripped/s/: [TAB] .*//p' | xargs -t strip

The find ( 17.2 ) finds all executable files that aren't setuid or setgid ( 24.14 ) and runs file ( 25.8 ) to get a description of each. The sed command skips shell scripts and other files that can't be stripped. sed searches for lines from file like:

/usr/local/bin/xemacs:
[TAB]


xxx

... executable 

xxx

... not stripped

with the word "executable" followed by "not stripped"- sed removes the colon, tab, and description, then passes the filename to strip .