Use $RANDOM in a makefile - shell

I am making a makefile to rename files with a random number in it (I am a newbie in shell script). I don't understand why, but when I run the file $rand is given the value 'ANDOM'. When I run this outside of the makefile it works.
I run this in the Mac os terminal, in case it's helpful.
all: renamefiles
renamefiles:
rand=$RANDOM && mv myfile.css $rand-myfile.css && mv myotherfile.css $rand-myotherfile.css

Wouldn't it be easier/better to use a date/time stamp so that the renamed files are listed in date order?
You need to use two $ signs in the makefile for each $ that you want the shell to see.
Thus:
all: renamefiles
renamefiles:
rand=$$RANDOM && \
mv myfile.css $$rand-myfile.css && \
mv myotherfile.css $$rand-myotherfile.css
Or, with date/time stamps:
all: renamefiles
renamefiles:
time=$$(date +'%Y%m%d-%H%M%S') && \
mv myfile.css $$time-myfile.css && \
mv myotherfile.css $$time-myotherfile.css

To use a random number within one or multiple make variables, the following works fine for me:
FOO="some string with \"$$rand\" in it"
BAR=" you may use it $$rand times."
foobar:
rand=$$$$ && \
echo $(FOO) $(BAR)

You might need to surround a multi-letter macro name with braces (or parentheses), for example
${RANDOM}
$(RANDOM)
ref

Related

ksh - why presence of the "\" file in current working directory changes behavior of variable processing

I had an issue with third party ksh script.
Found out, that it was failing because of file named "\" in user home directory.
Here is a simple testcase:
$ mkdir -p ~/dir1 && cd ~/dir1 && touch '\' && x="\* a" && echo $x
\ a
$ mkdir -p ~/dir2 && cd ~/dir2 && x="\* a" && echo $x
\* a
The question is, why the presence of "\" file in a working directory changes the result.
Is this expected?
Thanks.
T.
Looks like the expected behaviour.
If you want the same behaviour in both cases, either use set -o noglob inside your script, or run the script with the -f option to disable file name substitution.
The default is that the * is a special character when interpolating so will match whatever file exists (in your case dir1 will contain only one real file with the name of the backslash character.)
The second directory dir2 has no real files so ksh just shows the pattern exactly as you typed it.

Getting directory portion of a list of source files in a for loop

I have the following gnu make script:
for hdrfile in $(_PUBLIC_HEADERS) ; do \
echo $(dir $$hdrfile) ; \
done
The _PUBLIC_HEADERS variable has a list of relative paths, like so:
./subdir/myheader1.h
./subdir/myheader2.h
The output I get from the for loop above is:
./
./
I expect to see:
./subdir/
./subdir/
What am I doing wrong? Note that if I change the code to:
echo $(dir ./subdir/myheader1.h)
it works in this case. I think maybe it has something to do with the for loop but I'm not sure.
You are confusing make variables (or functions) with shell variables when executing the for-loop. Note that $(dir ...) is a make construct that gets expanded by make before the command is executed by the shell. However, you want the shell to execute that command inside the loop.
What you could do is replace $(dir) with the corresponding command dirname which gets executed by the shell. So it becomes:
for hdrfile in $(_PUBLIC_HEADERS) ; do \
dirname $$hdrfile ; \
done
This should give the desired result.

Makefile (counting)

I'm completely stumped on how to do this in a Makefile
Let's say I have a target. Inside the target I have a loop. How do i change a variable to keep track of the iterations?
For example:
COUNTER = 0
target:
(loop){
COUNTER++
echo COUNTER
}
I know that variables in Makefiles are only expanded, and I'm not sure if they can be permanently changed, but there has to be a way to do this, right? :(
Here are some sources that are asking similar questions. It seems like those examples only change the variable temporarily:
How do I perform arithmetic in a makefile?
How to do arithmetic operation in makefile?
Doing simple math in Makefile
Maybe I have to use the eval function somehow?
Maybe I have to append onto a Makefile string a character each time and then use something in the shell to count the characters?
If the variable doesn't have to survive the rule, this should do (I'm assuming bash):
clean:
#n=0 ; \
for x in $(THINGS_TO_BE_DELETED); do \
if [ -f $$x ] ; then \
rm $$x; \
let "n+=1" ; \
fi ; \
done ; \
echo deleted $$n files;
Here is one solution: Write a simple script like this:
#!/bin/bash
count=`cat count.txt`
count=$((count + 1))
echo $count
cat $count > count.txt
Initialize the file by doing
$ echo "0" > count.txt
Then include it as a .PHONY requirement to build whatever you'd like.
This is similar to the accepted answer, but the syntax below should work with a POSIX compliant shell. Quotes should also be used inside of the test.
clean:
#n=0; \
for x in *.a *.b *.c ; do \
if [ -f "$$x" ]; then \
rm "$$x"; \
n=$$((n+1)); \
fi; \
done; \
echo deleted $$n files;
Note: tabs must be used for indentation

How to ignore mv error?

I'm making a Makefile that moves an output file (foo.o) to a different directory (baz).
The output file moves as desired to the directory. However since make won't recompile the output file if I type make again, mv gets an error when it tries to move the non-existent empty file to the directory baz.
So this is what I have defined in my rule make all after all compilation:
-test -e "foo.o" || mv -f foo.o ../baz
Unfortunately, I'm still getting errors.
Errors in Recipes (from TFM)
To ignore errors in a recipe line, write a - at the beginning of the
line's text (after the initial tab).
So the target would be something like:
moveit:
-mv foo.o ../baz
I notice nobody has actually answered the original question itself yet, specifically how to ignore errors (all the answers are currently concerned with only calling the command if it won't cause an error).
To actually ignore errors, you can simply do:
mv -f foo.o ../baz 2>/dev/null; true
This will redirect stderr output to null, and follow the command with true (which always returns 0, causing make to believe the command succeeded regardless of what actually happened), allowing program flow to continue.
+#[ -d $(dir $#) ] || mkdir -p $(dir $#)
is what I use to silently create a folder if it does not exist. For your problem something like this should work
-#[ -e "foo.o" ] && mv -f foo.o ../baz
-test -e "foo.o" || if [ -f foo.o ]; then mv -f foo.o ../baz; fi;
That should work
Something like
test -e "foo.o" && mv -f foo.o ../baz
should work: the operator should be && instead of ||.
You can experiment with this by trying these commands:
test -e testfile && echo "going to move the file"
test -e testfile || echo "going to move the file"
I faced the same problem and as I am generating files, they always have different time. Workaround is set the same time to the files: touch -d '1 June 2018 11:02' file. In that case, gzip generates the same output and same md5sum. In my scenario, I don't need the time for the files.

Getting the name of the makefile from the makefile

How to get the name of the makefile in the makefile?
Thanks.
Note:
I would need that because I would like my makefile to call itself, but the makefile is not called Makefile, so I'd like to write something like this:
target:
($MAKE) -f ($MAKEFILENAME) other_target
location = $(CURDIR)/$(word $(words $(MAKEFILE_LIST)),$(MAKEFILE_LIST))
WHERE_ART_THOU := $(location)
$(warning $(WHERE_ART_THOU))
I also believe this is GNU make-specific, but I'm not too sure.
(Should you have any questions, refer to amazingly written GNU make manual. But remember, that, just like Makefile, this manual should be read completely before putting the concepts into practice).
I couldn't figure out how it is done easily. As far as I understand, you'll have to do some manual job.
Later I will describe how it could be done and show scripts that introduce current_makefile variable. But I would like to stress an important concept at the first place.
You should understand that if we had some kind of variable current_makefile, that expands to the current makefile name, then it will have to change during the process of reading makefiles. That means that it should be used withinin "immediate" expansion context -- i.e. within commands that are executed during reading the makefile. Most commands, however, are executed after makefiles are read. Therefore, some commands will print the correct value smoothly, while in certain places, where "deferred" expansion is used, it will always expand to the root makefile name.
If you would want to use this variable within rule text, for example, you'll have to do tricks, because rule text always has deferred expansion. So, if your have the rule
rule:
echo In makefile $(current_makefile):
echo Making target $#
it will always print the name of the root makefile. Instead, to force immediate expansion, you will have to create another variable with makefile-specific name (i.e. names of such variables should be different in each makefile):
this_makefile_unique_name := $(current_makefile)
rule:
echo In makefile $(current_makefile):
echo Making target $#
or use eval:.
define make_rule
rule:
echo In makefile $(1):
echo Making target $$#
$(eval $(call make_rule,$(current_makefile)))
If you want to use the name of current makefile for debug purpose only, consider special debugging functions, like warning or info:.
$(warning We're in makefile $(current_makefile))
These functions use "immediate" expansion and will print the correct value.
How to define such a $(current_makefile)?
You have to manually maintain stack of makefile inclusions. When you include a makefile, its name is placed to the top of the stack; when you return from included makefile to the outer one, the topmost name is popped out of stack. This is achieved by inserting special calls to the beginning and the end of makefile:
# Beginning of makefile
$(eval $(makefile_names_push))
#... makefile text
$(warning $(current_makefile))
#...
$(eval $(makefile_names_pop))
#End of file
Now define the functions at the beginning of your root makefile.
lastword=$(word $(words $(1)),$(1))
define makefile_names_push
current_makefile := $$(CURDIR)/$$(call lastword,$$(MAKEFILE_LIST))
makefile_stack :=$$(makefile_stack) $$(current_makefile)
endef
define makefile_names_pop
makefile_stack := $$(filter-out $$(current_makefile),$$(makefile_stack))
current_makefile := $$(call lastword,$$(makefile_stack))
endef
If you're sure your make is new enough (version 3.81+), replace lastword call with builtin function:.
#inctead of $$(call lastword,$$(MAKEFILE_LIST))
$$(lastword $$(MAKEFILE_LIST))
Is it useful?
Totally useless. An only use that might be useful here is to make 100 makefiles that are symlinks to one makefile, the rules in these makefiles depending on their names. But it can be achieved within one makefile and foreach-eval technique described in the manual. So my post was a complete waste of time, though I had some fun :-)
This returns the name of the first Makefile called, i.e. the one at the bottom of the call stack:
MAKEFILE_JUSTNAME := $(firstword $(MAKEFILE_LIST))
MAKEFILE_COMPLETE := $(CURDIR)/$(MAKEFILE_JUSTNAME)
When used in non-cross-recursive situations (e.g. for makedepend), it is just the name of the current makefile.
I wanted to do something similar (for echoing the contents of the Makefile) for when I use Make for managing simple repetitive tasks. I came across this page and found it was exactly what I was after and really useful for my limited understanding of make.
My result after reading this page:
# Makefile - 'make' and 'make help' now echo the makefile.
help:
cat $(lastword $(MAKEFILE_LIST))
start:
sudo -u www /path/to/webapp/myhttpd restart
stop:
sudo kill `cat /path/to/webapp/data/httpd.pid`
A quick excursion to Google suggests this site has the answer.
G'day,
If you make a copy of your original makefile, say makefile_test, and then enter the command:
make -np -f makefile_test 2>&1 | tee output
That will evaluate the makefile and your make environment but not execute any of the commands. Looking through the output file for references to makefile_test will show you what is set in make's environment and where that value is being set.
N.B. This can generate a lot of info! And don't add the -d (debug) switch which will generate tons of additional output about make's decision process but minimal additional info about make's env.
HTH
The solutions here addresses 1) POSIX make with 2) Invoked, non included, makefile in 3) A Unix alike platform.
What the OP asked for:
target:
#pid=$$$$; \
while test `ps -ocomm= $$pid` != make; do \
pid=`ps -oppid= $$pid`; \
done; \
MAKEFILENAME=`ps -oargs= $$pid|sed 's/^.* -f *\([^ ]*\).*$$/\1/'`; \
test -z "$$MAKEFILENAME" -a -f Makefile && MAKEFILENAME=Makefile; \
test -z "$$MAKEFILENAME" -a -f makefile && MAKEFILENAME=makefile; \
export MAKEFILENAME; \
$(MAKE) -e -f $$MAKEFILENAME other_target
The targets depends on the makefile, kind of bloated:
TARGET1_MAKEFILENAME = target1_preamble
all: target1 target2...
target1: $(TARGET1_MAKEFILENAME) other_dependencies...
#test $(TARGET1_MAKEFILENAME) == target1_preamble && exit 0; \
built_instructions_for_target1;
target1_preamble:
#pid=$$$$; \
while test `ps -ocomm= $$pid` != make; do \
pid=`ps -oppid= $$pid`; \
done; \
MAKEFILENAME=`ps -oargs= $$pid|sed 's/^.* -f *\([^ ]*\).*$$/\1/'`; \
test -z "$$MAKEFILENAME" -a -f Makefile && MAKEFILENAME=Makefile; \
test -z "$$MAKEFILENAME" -a -f makefile && MAKEFILENAME=makefile; \
export MAKEFILENAME; \
$(MAKE) -e -f $$MAKEFILENAME target1;
Can be a bit simplified if make is invoked only for all targets.
MAKEFILENAME = invoked_makefile_placeholder
all: target1 target2...
target1: $(MAKEFILENAME) other_dependencies...
#test $(MAKEFILENAME) == invoked_makefile_placeholder && exit 0; \
built_instructions_for_target1;
invoked_makefile_placeholder:
#pid=$$$$; \
while test `ps -ocomm= $$pid` != make; do \
pid=`ps -oppid= $$pid`; \
done; \
MAKEFILENAME=`ps -oargs= $$pid|sed 's/^.* -f *\([^ ]*\).*$$/\1/'`; \
test -z "$$MAKEFILENAME" -a -f Makefile && MAKEFILENAME=Makefile; \
test -z "$$MAKEFILENAME" -a -f makefile && MAKEFILENAME=makefile; \
export MAKEFILENAME; \
$(MAKE) -e -f $$MAKEFILENAME
With the previous approach is trivial to implement a solution for included makefiles based in grep and a unique pattern contained in the makefile.
I never answer when I feel the question got a proper solution.

Resources