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Previous: 24.12 Compressing a Directory Tree: Fine-Tuning Chapter 24
Other Ways to Get Disk Space
Next: 24.14 Don't Use strip Carelessly
 

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 .

- JP


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