I'm looking for a simple bash script which, when given the name of a system header, will return its full path from which it would be read in a #include <header> statement. I already have an analogous thing for looking up the library archive used by linker.
ld -verbose -lz -L/some/other/dir | grep succeeded | sed -e 's/^\s*attempt to open //' -e 's/ succeeded\s*$//'
For example, this will return the path of libz archive (/lib/x86_64-linux-gnu/libz.so on my system).
For the requested script I know that I could take a list of include directories used by gcc and search them for the file myself, but I'm looking for a more accurate simulation of what's happening inside the preprocessor (unless it's that simple).
Pipe the input to preprocessor and then process the output. Gcc preprocessor output inserts # lines with information and flags that you can parse.
$ f=stdlib.h
$ echo "#include <$f>" | gcc -xc -E - | sed '\~# [0-9]* "\([^"]*/'"$f"'\)" 1 .*~!d; s//\1/'
/usr/include/stdlib.h
It can output multiple files, because gcc has #include_next and can improperly detect in some complicated cases where multiple filenames are included with the same name, like in f=limits.h. So you could also filter exactly second line, knowing that the first line is always going to be stdc-predef.h:
$ f=limits.h; echo "#include <$f>" | gcc -xc -E - | sed '/# [0-9]* "\([^"]*\)" 1 .*/!d;s//\1/' | sed '2!d'
/usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/include-fixed/limits.h
But really search the include paths yourself, it's not that hard:
$ f=limits.h; echo | gcc -E -Wp,-v - 2>&1 | sed '\~^ /~!d; s/ //' | while IFS= read -r path; do if [[ -e "$path/$f" ]]; then echo "$path/$f"; break; fi; done
/usr/lib/gcc/x86_64-pc-linux-gnu/10.1.0/include-fixed/limits.h
You can use the preprocessor to do the work:
user#host:~$ echo "#include <stdio.h>" > testx.c && gcc -M testx.c | grep 'stdio.h'
testx.o: testx.c /usr/include/stdc-predef.h /usr/include/stdio.h \
You can add a bit bash-fu to cut the part you are interested in
After spending almost an hour on filtering output of
clang -v hello_world.c
I got the following linking command:
ld -m elf_x86_64 -dynamic-linker /lib64/ld-linux-x86-64.so.2 \
/usr/lib/x86_64-linux-gnu/crt1.o /usr/lib/x86_64-linux-gnu/crti.o \
hello_world.o /usr/lib/x86_64-linux-gnu/libc.so \
/usr/lib/x86_64-linux-gnu/crtn.o
Is there an easier way to find out that -lc will expand to /usr/lib/x86_64-linux-gnu/libc.so?
I need to know which files are used so I can copy them to another system for cross compiling.
edit
Looks like I should use the cross-compile toolchain. From clang docs:
https://clang.llvm.org/docs/CrossCompilation.html
When you have extracted your cross-compiler from a zip file into a
directory, you have to use --sysroot=. The path is the root
directory where you have unpacked your file, and Clang will look for
the directories bin, lib, include in there.
Where can I get that zip file they refer to? I'm interested in x86_64-linux-gnu target.
This will list all the files linked to libc.so.6:
for i in `find . -type f -executable`
do
j=$(ldd $i | grep libc.so.6 | wc -l)
if [ $j -gt 0 ]
then
echo $i
fi
done
In case you want to find out what the path of libc.so.6 is, stated in the original question something similar to:
ldd `which ld` | sed 's/^[[:space:]]libc.so.6[[:space:]]=>[[:space:]]\(.*\)[[:space:]](.*)/\1/p' | grep --color=never libc.so
will type the path, you can obviously replace the expression after ldd with any filename.
From the comments, there is a way with clang directly though it will generate a lot of noise which is significantly harder to exclude compared to the ldd way.
clang -Wl,--verbose hello_world.c
will tell the linker to be verbose and it will eventually tell you all the library paths tried for each library.
I have 25 object files which are combined to form one shared library. I have generated the shared library with gcc and while I was looking for exposed symbols with nm -D libmylib.so, I found two undesirable exposed symbols with the name of i and y which are in .bss section. I have tried to find them in my source files but i cant find them so if anyone can tell me whether there is some way to find that which .o file exactly has these undesired exposed symbols? Can I do it with nm or do I need another tool?
Any help would be appreciated.
Once the shared library is linked, you can no longer tell which parts of it came from which object file.
You can search the individual objects from which you build the library:
find . -name '*.o' -print0 | xargs -0 nm -A | egrep ' (i|y)$'
You can ask the linker to tell you when they are defined:
$(CC) -fPIC -shared -o libmy.so $(OBJS) -Wl,-y,i,-y,y
If you built the library from objects compiled with -g, you may ask GDB where i and y came from:
gdb -q libmy.so
(gdb) info var ^i$
(gdb) info var ^y$
In the directory with your object files you can run:
find . -name '*.o' -exec nm -D {} \; -print
This should print symbols and then file name
I've got a folder in linux, which is contained several shared object files (*.so). How I can find function in shared object files using objdump and bash functions in linux?
For instance, the following example is found me function func1 in mylib.so:
objdump -d mylib.so | grep func1
But i want to find func1 in folder which is contained shared object files. I don't know bash language and how to combinate linux terminal commands.
nm is simpler than objdump, for this task.
nm -A *.so | grep func should work. The -A flag tells nm to print the file name.
You can use also use,
find <path> -name "*.so" -exec nm {} \; | grep func1
How do I find out the files in the current directory which do not contain the word foo (using grep)?
If your grep has the -L (or --files-without-match) option:
$ grep -L "foo" *
You can do it with grep alone (without find).
grep -riL "foo" .
This is the explanation of the parameters used on grep
-L, --files-without-match
each file processed.
-R, -r, --recursive
Recursively search subdirectories listed.
-i, --ignore-case
Perform case insensitive matching.
If you use l (lowercased) you will get the opposite (files with matches)
-l, --files-with-matches
Only the names of files containing selected lines are written
Take a look at ack. It does the .svn exclusion for you automatically, gives you Perl regular expressions, and is a simple download of a single Perl program.
The equivalent of what you're looking for should be, in ack:
ack -L foo
The following command gives me all the files that do not contain the pattern foo:
find . -not -ipath '.*svn*' -exec grep -H -E -o -c "foo" {} \; | grep 0
The following command excludes the need for the find to filter out the svn folders by using a second grep.
grep -rL "foo" ./* | grep -v "\.svn"
If you are using git, this searches all of the tracked files:
git grep -L "foo"
and you can search in a subset of tracked files if you have ** subdirectory globbing turned on (shopt -s globstar in .bashrc, see this):
git grep -L "foo" -- **/*.cpp
You will actually need:
find . -not -ipath '.*svn*' -exec grep -H -E -o -c "foo" {} \; | grep :0\$
I had good luck with
grep -H -E -o -c "foo" */*/*.ext | grep ext:0
My attempts with grep -v just gave me all the lines without "foo".
Problem
I need to refactor a large project which uses .phtml files to write out HTML using inline PHP code. I want to use Mustache templates instead. I want to find any .phtml giles which do not contain the string new Mustache as these still need to be rewritten.
Solution
find . -iname '*.phtml' -exec grep -H -E -o -c 'new Mustache' {} \; | grep :0$ | sed 's/..$//'
Explanation
Before the pipes:
Find
find . Find files recursively, starting in this directory
-iname '*.phtml' Filename must contain .phtml (the i makes it case-insensitive)
-exec 'grep -H -E -o -c 'new Mustache' {}' Run the grep command on each of the matched paths
Grep
-H Always print filename headers with output lines.
-E Interpret pattern as an extended regular expression (i.e. force grep
to behave as egrep).
-o Prints only the matching part of the lines.
-c Only a count of selected lines is written to standard output.
This will give me a list of all file paths ending in .phtml, with a count of the number of times the string new Mustache occurs in each of them.
$> find . -iname '*.phtml$' -exec 'grep -H -E -o -c 'new Mustache' {}'\;
./app/MyApp/Customer/View/Account/quickcodemanagestore.phtml:0
./app/MyApp/Customer/View/Account/studio.phtml:0
./app/MyApp/Customer/View/Account/orders.phtml:1
./app/MyApp/Customer/View/Account/banking.phtml:1
./app/MyApp/Customer/View/Account/applycomplete.phtml:1
./app/MyApp/Customer/View/Account/catalogue.phtml:1
./app/MyApp/Customer/View/Account/classadd.phtml:0
./app/MyApp/Customer/View/Account/orders-trade.phtml:0
The first pipe grep :0$ filters this list to only include lines ending in :0:
$> find . -iname '*.phtml' -exec grep -H -E -o -c 'new Mustache' {} \; | grep :0$
./app/MyApp/Customer/View/Account/quickcodemanagestore.phtml:0
./app/MyApp/Customer/View/Account/studio.phtml:0
./app/MyApp/Customer/View/Account/classadd.phtml:0
./app/MyApp/Customer/View/Account/orders-trade.phtml:0
The second pipe sed 's/..$//' strips off the final two characters of each line, leaving just the file paths.
$> find . -iname '*.phtml' -exec grep -H -E -o -c 'new Mustache' {} \; | grep :0$ | sed 's/..$//'
./app/MyApp/Customer/View/Account/quickcodemanagestore.phtml
./app/MyApp/Customer/View/Account/studio.phtml
./app/MyApp/Customer/View/Account/classadd.phtml
./app/MyApp/Customer/View/Account/orders-trade.phtml
When you use find, you have two basic options: filter results out after find has completed searching or use some built in option that will prevent find from considering those files and dirs matching some given pattern.
If you use the former approach on a high number of files and dirs. You will be using a lot of CPU and RAM just to pass the result on to a second process which will in turn filter out results by using a lot of resources as well.
If you use the -not keyword which is a find argument, you will be preventing any path matching the string on the -name or -regex argument behind from being considered, which will be much more efficient.
find . -not -regex ".*/foo/.*" -regex ".*"
Then, any path that is not filtered out by -not will be captured by the subsequent -regex arguments.
For completeness the ripgrep version:
rg --files-without-match "pattern"
You can combine with file type and search path, e.g.
rg --files-without-match -t ruby "frozen_string_literal: true" app/
another alternative when grep doesn't have the -L option (IBM AIX for example), with nothing but grep and the shell :
for file in * ; do grep -q 'my_pattern' $file || echo $file ; done
My grep does not have any -L option. I do find workaround to achieve this.
The ideas are :
to dump all the file name containing the deserved string to a txt1.txt.
dump all the file name in the directory to a txt2.txt.
make the difference between the 2 dump file with diff command.
grep 'foo' *.log | cut -c1-14 | uniq > txt1.txt
grep * *.log | cut -c1-14 | uniq > txt2.txt
diff txt1.txt txt2.txt | grep ">"
find *20161109* -mtime -2|grep -vwE "(TRIGGER)"
You can specify the filter under "find" and the exclusion string under "grep -vwE". Use mtime under find if you need to filter on modified time too.
Open bug report
As commented by #tukan, there is an open bug report for Ag regarding the -L/--files-without-matches flag:
ggreer/the_silver_searcher: #238 - --files-without-matches does not work properly
As there is little progress to the bug report, the -L option mentioned below should not be relied on, not as long as the bug has not been resolved. Use different approaches presented in this thread instead. Citing a comment for the bug report [emphasis mine]:
Any updates on this? -L completely ignores matches on the first line of the file. Seems like if this isn't going to be fixed soon, the flag should be removed entirely, as it effectively does not work as advertised at all.
The Silver Searcher - Ag (intended function - see bug report)
As a powerful alternative to grep, you could use the The Silver Searcher - Ag:
A code searching tool similar to ack, with a focus on speed.
Looking at man ag, we find the -L or --files-without-matches option:
...
OPTIONS
...
-L --files-without-matches
Only print the names of files that don´t contain matches.
I.e., to recursively search for files that do not match foo, from current directory:
ag -L foo
To only search current directory for files that do not match foo, simply specify --depth=0 for the recursion:
ag -L foo --depth 0
This may help others. I have mix of files Go and with test files. But I only need .go files. So I used
ls *.go | grep -v "_test.go"
-v, --invert-match select non-matching lines see https://stackoverflow.com/a/3548465
Also one can use this with vscode to open all the files from terminal
code $(ls *.go | grep -v "_test.go")
grep -irnw "filepath" -ve "pattern"
or
grep -ve "pattern" < file
above command will give us the result as -v finds the inverse of the pattern being searched
The following command could help you to filter the lines which include the substring "foo".
cat file | grep -v "foo"