How to split in GNU makefile list of files into separate lines

Question

I have a variable containing list of files separated with string _NEWLINE_. I need to output that variable into a file so that each file is in a separate line. The trick is that it needs to works on FreeBSD and Solaris.

This is what I am trying now:

echo "lib/alarms-1.2/priv/snmp_conf/agent.conf: lib/alarms/priv/snmp_conf/agent.conf_NEWLINE_lib/alarms-1.2/priv/snmp_conf/agent.conf.src: lib/alarms/priv/snmp_conf/agent.conf.src_NEWLINE_lib/alarms-1.2/priv/snmp_conf/community.conf: lib/alarms/priv/snmp_conf/community.conf" | sed 's|_NEWLINE_|\'$'\n|g'

This works on FreeBSD and in shell on Solaris. But when run in GNUmakefile on Solaris I am getting this (notice $ at the end of each line):

lib/alarms-1.2/priv/snmp_conf/agent.conf: lib/alarms/priv/snmp_conf/agent.conf$
lib/alarms-1.2/priv/snmp_conf/agent.conf.src: lib/alarms/priv/snmp_conf/agent.conf.src$
lib/alarms-1.2/priv/snmp_conf/community.conf: lib/alarms/priv/snmp_conf/community.conf$

If I remove \'$' from sed then it works on Solaris but doesn't on FreeBSD. Maybe there is a way of telling which version to use depending on which system the makefile is executed?

EDIT: Thanks to the solution proposed by bobbogo I created an exemplary makefile that provides the desired outcome and seems to be working on both FreeBSD and Solaris:

one-line := lib/alarms-1.2/priv/snmp_conf/agent.conf: lib/alarms/priv/snmp_conf/agent.conf_NEWLINE_lib/alarms-1.2/\
priv/snmp_conf/agent.conf.src: lib/alarms/priv/snmp_conf/agent.conf.src_NEWLINE_lib/alarms-1.2/priv/snmp_conf/comm\
unity.conf: lib/alarms/priv/snmp_conf/community.conf

many-lines := { echo '$(subst _NEWLINE_,' && echo ',${one-line})'; }

.PHONY: all
all:
  $(shell $(many-lines) > test.txt)

Answer 1

If this is GNU make, then do it all in make.

one-line := lib/alarms-1.2/priv/snmp_conf/agent.conf: lib/alarms/priv/snmp_conf/agent.conf_NEWLINE_lib/alarms-1.2/priv/snmp_conf/agent.conf.src: lib/alarms/priv/snmp_conf/agent.conf.src_NEWLINE_lib/alarms-1.2/priv/snmp_conf/community.conf: lib/alarms/priv/snmp_conf/community.conf

define \n


endef

many-lines := $(subst _NEWLINE_,${\n},${one-line})

Now ${many-lines} has just what you want. Annoyingly, it's quite hard to use in shell lines. If you do this:

tgt:
    echo '${many-lines}'

make will invoke a separate shell for each line. The first shell invocation will get an un-paired ' and exit with an error.

.ONESHELL:
tgt:
    echo '${many-lines}'

will work in an invasive sort of way. The proper fix is to ensure each line of ${many-lines} has valid sh syntax. Some mouthfull like:

echolines = $(subst ${\n},'${\n}echo ',echo '${many-lines}')
.PHONY: aa
aa:
    $(call echolines,${many-lines})

Sheesh.

Answer 2

Tried many different solutions, including defining \n as mentioned in this answer: Add a newline in Makefile 'foreach' loop

The real problem is inconsistent implementation of the echo command across platforms, and the fact that by default make invokes shell commands using sh, which itself is quite inflexible.

I found a better way thanks to this answer: "echo -e" when called directly and when called via a shell-script

The better way is to use printf instead of echo

Construct the string with \n instead of _NEWLINE_ to separate parts that go into separate lines in the output file:

some_string = lib/alarms-1.2/priv/snmp_conf/target_params.conf: lib/alarms/priv/snmp_conf/target_params.conf\nlib/alarms-1.2/priv/snmp_conf/community.conf: lib/alarms/priv/snmp_conf/community.conf\n

and then in the makefile print it simply as this:

@printf "$(some_string)" >> $(some_file)

Works on both, FreeBSD and Solaris.

Answer 3

Disclaimer: I have no experience with Solaris or FreeBSD... here goes anyway.

In make, you can use $(patsubst pattern,replacement,text) to substitute a pattern. try this...

FILENAMES := "lib/alarms-1.2/priv/snmp_conf/agent.conf: lib/alarms/priv/snmp_conf/agent.conf_NEWLINE_lib/alarms-1.2/priv/snmp_conf/agent.conf.src: lib/alarms/priv/snmp_conf/agent.conf.src_NEWLINE_lib/alarms-1.2/priv/snmp_conf/community.conf: lib/alarms/priv/snmp_conf/community.conf"

.PHONY: all

all:
    @echo $(patsubst _NEWLINE_,${\n},$(FILENAMES))

Answer 4

As an alternative, I think your first approach will work, if you just double the $ to "escape" it:

sed 's|_NEWLINE_|\'$$'\n|g'