In one of my Makefile recipes, I want to create a temporary file, pass the name of that file to a shell command and assign the output of that command to a make variable so that I can use that subsequently. For the life of me, I cannot get it to work.
For the purpose of debugging I have tried to boil down the problem to the most simple target I could come up with:
.PHONY: foo
foo:
$(eval TMPFILE = $(shell mktemp -p ./))
dd if=/dev/random of=${TMPFILE} bs=1 count=512
$(eval FOO = $(shell wc -c ${TMPFILE}))
#echo FOO: ${FOO}
Here is what happens:
❯ make foo
dd if=/dev/random of=./tmp.K1au4WrZ76 bs=1 count=512
512+0 records in
512+0 records out
512 bytes copied, 0.00287818 s, 178 kB/s
FOO: 0 ./tmp.K1au4WrZ76
So somehow, wc thinks the file is empty. But when I check the TMPFILE it has 512 bytes, as expected:
❯ wc -c tmp.K1au4WrZ76
512 tmp.K1au4WrZ76
Can someone, please enlighten me what is going on here and how to do that correctly?
Thanks
Phil
Update: Based on the answer I put together this target which works as desired:
.PHONEY: foo
.ONESHELL:
foo:
set -e
TMPFILE=`mktemp -p ./`
dd if=/dev/random of=$$TMPFILE bs=1 count=512
FOO=`wc -c $$TMPFILE`
#echo FOO: $$FOO
Thanks!
Make always expands the entire recipe (all lines of the recipe) first, before it starts any shell commands. So all your eval, etc. operations are invoked before any shell command, such as dd, is run.
Updated :
Initial issue :
Having a while read loop printing every line that is read
Answer : Put a done <<< "$var"
Subsequent issue :
I may need some explanations about some SHELL code :
I have this :
temp_ip=$($mysql --skip-column-names -h $db_address -u $db_user -p$db_passwd $db_name -e "select ip_routeur,code_site from $db_vtiger_table where $db_vtiger_table.ip_routeur NOT IN (select ip from $db_erreur_table);")
That gets results looking like this :
<ip1> <site1>
<ip2> <site2>
<ip3> <site3>
<ip4> <site4>
up to 5000 ip_address
I did a "while loop" :
while [ `find $proc_dir -name snmpproc* | wc -l` -ge "$max_proc_snmpget" ];do
{
echo "sleeping, fping in progress";
sleep 1;
}
done
temp_ip=$($mysql --skip-column-names -h $db_address -u $db_user -p$db_passwd $db_name -e "select ip_routeur,code_site from $db_vtiger_table where $db_vtiger_table.ip_routeur NOT IN (select ip from $db_erreur_table);")
while read ip codesite;do
{
sendSNMPGET $ip $snmp_community $code_site &
}
done<<<"$temp_ip"
And the sendSNMPGET function is :
sendSNMPGET() {
touch $procdir/snmpproc.$$
hostname=`snmpget -v1 -c $2 $1 sysName.0`
if [ "$hostname" != "" ]
then
echo "hi test"
fi
rm -f $procdir/snmpproc.$$
The $max_proc_snmpget is set to 30
At the execution, the read is ok, no more printing on screen, but child processes seems to be disoriented
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
hi
./scan-snmp.sh: fork: Resource temporarily unavailable
./scan-snmp.sh: fork: Resource temporarily unavailable
./scan-snmp.sh: fork: Resource temporarily unavailable
./scan-snmp.sh: fork: Resource temporarily unavailable
Why can't it handle this ?
If temp_ip contains the name of a file that you want to read, then use:
done<"$temp_ip"
In your case, it appears that temp_ip is not a file name but contains the actual data that you want. In that case, use:
done<<<"$temp_ip"
Take care that the variable is placed inside double-quotes. That protects the data against the shell's word splitting which would result in the replacement of new line characters with spaces.
More details
In bash, an expression like <"$temp_ip" is called redirection. In this case in means that the while loop will get its standard input from the file called $temp_ip.
The expression <<<"$temp_ip" is called a here string. In this case, it means that the while loop will get its standard input from the data in the variable $temp_ip.
More information on both redirection and here strings in man bash.
Or you can parse the output of your initial command directly:
$mysql --skip-column-names -h $db_address -u $db_user -p$db_passwd $db_name -e "select ip_routeur,code_site from $db_vtiger_table where $db_vtiger_table.ip_routeur NOT IN (select ip from $db_erreur_table) | \
while read ip codesite
do
...
done
If you want to improve the performance and run some of the 5,000 SNMPGETs in parallel, I would recommend using GNU Parallel (here) like this:
$mysql --skip-column-names -h $db_address -u $db_user -p$db_passwd $db_name -e "select ip_routeur,code_site from $db_vtiger_table where $db_vtiger_table.ip_routeur NOT IN (select ip from $db_erreur_table) | parallel -k -j 20 -N 2 sendSNMPGET {1} $snmp_community {2}
The -k will keep the parallel output in order. The -j 20 will run up to 20 SNMPGETs in parallel at a time. The -N 2 means take 2 parameters from the mysql output per job (i.e. ip and codesite). {1} and {2} are your ip and codesite parameters.
http://www.gnu.org/software/parallel/
I propose to not store the result value but use it directly:
while read ip codesite
do
sendSNMPGET "$ip" "$snmp_community" "$code_site" &
done < <(
"$mysql" --skip-column-names -h "$db_address" -u "$db_user" -p"$db_passwd" "$db_name" \
-e "select ip_routeur,code_site from $db_vtiger_table where $db_vtiger_table.ip_routeur NOT IN (select ip from $db_erreur_table);")
This way you start the mysql command in a subshell and use its output as input to the while loop (similar to piping which here also is an option).
But I see some problems with that code: If you really start each sendSNMPGET command in the background, you very quickly will put a massive load on your computer. For each line you read another active background process is started. This can slow down your machine to the point where it is rendered useless.
I propose to not run more than 20 background processes at a time.
As you don't seem to have liked my answer with GNU Parallel, I'll show you a very simplistic way of doing it in parallel without needing to install that...
#!/bin/bash
MAX=8
j=0
while read ip code
do
(sleep 5; echo $ip $code) & # Replace this with your SNMPGET
((j++))
if [ $j -eq $MAX ]; then
echo -n Pausing with $MAX processes...
j=0
wait
fi
done < file
wait
This starts up to 8 processes (you can change it) and then waits for them to complete before starting another 8. You have already been shown how to feed your mysql stuff into the loop by other respondents in the second to last line of the script...
The key to this is the wait which will wait for all started processes to complete.
How can I implement a simple regression test framework with Make? (I’m using GNU Make, if that matters.)
My current makefile looks something like this (edited for simplicity):
OBJS = jscheme.o utility.o model.o read.o eval.o print.o
%.o : %.c jscheme.h
gcc -c -o $# $<
jscheme : $(OBJS)
gcc -o $# $(OBJS)
.PHONY : clean
clean :
-rm -f jscheme $(OBJS)
I’d like to have a set of regression tests, e.g., expr.in testing a “good” expression & unrecognized.in testing a “bad” one, with expr.cmp & unrecognized.cmp being the expected output for each. Manual testing would look like this:
$ jscheme < expr.in > expr.out 2>&1
$ jscheme < unrecognized.in > unrecognized.out 2>&1
$ diff -q expr.out expr.cmp # identical
$ diff -q unrecognized.out unrecognized.cmp
Files unrecognized.out and unrecognized.cmp differ
I thought to add a set of rules to the makefile looking something like this:
TESTS = expr.test unrecognized.test
.PHONY test $(TESTS)
test : $(TESTS)
%.test : jscheme %.in %.cmp
jscheme < [something.in] > [something.out] 2>&1
diff -q [something.out] [something.cmp]
My questions:
• What do I put in the [something] placeholders?
• Is there a way to replace the message from diff with a message saying, “Test expr failed”?
Your original approach, as stated in the question, is best. Each of your tests is in the form of a pair of expected inputs and outputs. Make is quite capable of iterating through these and running the tests; there is no need to use a shell for loop. In fact, by doing this you are losing the opportunity to run your tests in parallel, and are creating extra work for yourself in order to clean up temp files (which are not needed).
Here's a solution (using bc as an example):
SHELL := /bin/bash
all-tests := $(addsuffix .test, $(basename $(wildcard *.test-in)))
.PHONY : test all %.test
BC := /usr/bin/bc
test : $(all-tests)
%.test : %.test-in %.test-cmp $(BC)
#$(BC) <$< 2>&1 | diff -q $(word 2, $?) - >/dev/null || \
(echo "Test $# failed" && exit 1)
all : test
#echo "Success, all tests passed."
The solution directly addresses your original questions:
The placeholders you're looking for are $< and $(word 2, $?) corresponding to the prerequisites %.test-in and %.test-cmp respectively. Contrary to the #reinierpost comment temp files are not needed.
The diff message is hidden and replaced using echo.
The makefile should be invoked with make -k to run all the tests regardless of whether an individual test fails or succeeds.
make -k all will only run if all the tests succeed.
We avoid enumerating each test manually when defining the all-tests variable by leveraging the file naming convention (*.test-in) and the GNU make functions for file names. As a bonus this means the solution scales to tens of thousands of tests out of the box, as the length of variables is unlimited in GNU make. This is better than the shell based solution which will fall over once you hit the operating system command line limit.
Make a test runner script that takes a test name and infers the input filename, output filename and smaple data from that:
#!/bin/sh
set -e
jscheme < $1.in > $1.out 2>&1
diff -q $1.out $1.cmp
Then, in your Makefile:
TESTS := expr unrecognised
.PHONY: test
test:
for test in $(TESTS); do bash test-runner.sh $$test || exit 1; done
You could also try implementing something like automake's simple test framework.
What I ended up with looks like this:
TESTS = whitespace list boolean character \
literal fixnum string symbol quote
.PHONY: clean test
test: $(JSCHEME)
for t in $(TESTS); do \
$(JSCHEME) < test/$$t.ss > test/$$t.out 2>&1; \
diff test/$$t.out test/$$t.cmp > /dev/null || \
echo Test $$t failed >&2; \
done
It’s based on Jack Kelly’s idea, with Jonathan Leffler’s tip included.
I'll address just your question about diff. You can do:
diff file1 file2 > /dev/null || echo Test blah blah failed >&2
although you might want to use cmp instead of diff.
On another note, you might find it helpful to go ahead and take
the plunge and use automake. Your Makefile.am (in its entirety)
will look like:
bin_PROGRAMS = jscheme
jscheme_SOURCES = jscheme.c utility.c model.c read.c eval.c print.c jscheme.h
TESTS = test-script
and you will get a whole lot of really nice targets for free, including a pretty full-featured test framework.
Does anyone know how to set a variable with global scope in a KSH if, case, or loop statement?
I am trying to run the following code but the script only echo's "H" instead of the actual value seen in the input file.
CFG_DIR=${WORK_DIR}/cfg
CFG_FILE=${CFG_DIR}/$1
NAME=$(echo $CFG_FILE | cut -f1 -d\.)
UPPER_BUS_NETWORK="H"
cat ${CFG_FILE} | grep -v ^\# |
while read CLINE
do
PROPERTY=$(echo $CLINE | cut -f1 -d\=)
VALUE=$(echo $CLINE | cut -f2 -d\=)
if [ ${PROPERTY} = "UpperBusService" ]; then
UPPER_BUS_SERVICE="${VALUE}"
fi
if [ ${PROPERTY} = "UpperBusNetwork" ]; then
UPPER_BUS_NETWORK="${VALUE}"
fi
done
echo ${UPPER_BUS_NETWORK}
Are you sure you're running that in ksh? Which version? Ksh93 doesn't set up a subshell in a while loop. Bash, dash, ash and pdksh do, though. I'm not sure about ksh88.
Compare
$ bash -c 'a=111; echo foo | while read bar; do echo $a; a=222; echo $a; done; echo "after: $a"'
111
222
after: 111
to
ksh -c 'a=111; echo foo | while read bar; do echo $a; a=222; echo $a; done; echo "after: $a"'
111
222
after: 222
Zsh gives the same result as ksh93.
Unfortunately, pdksh doesn't support process substitution and ksh93 does, but not when redirected into the done of a while loop, so the usual solution which works in Bash is not available. This is what it would look like:
# Bash (or Zsh)
while read ...
do
...
done < <(command)
Using a temporary file may be the only solution:
command > tmpfile
while read
do
...
done < tmpfile
Some additional notes:
Instead of cat ${CFG_FILE} | grep -v ^\# do grep -v ^\# "${CFG_FILE}"
Usually, you should use read -r so backslashes are handled literally
Instead of NAME=$(echo $CFG_FILE | cut -f1 -d\.) you should be able to do something like NAME=${CFG_FILE%%.*} and VALUE=${#*=}; VALUE=${VALUE%%=*}
Variables should usually be quoted on output, for example in each of your echo statements and your cat command
I recommend the habit of using lowercase or mixed case variable names to avoid conflict with shell variables (though none are present in your posted code)
I want to create a makefile variable that is a multi-line string (e.g. the body of an email release announcement). something like
ANNOUNCE_BODY="
Version $(VERSION) of $(PACKAGE_NAME) has been released
It can be downloaded from $(DOWNLOAD_URL)
etc, etc"
But I can't seem to find a way to do this. Is it possible?
Yes, you can use the define keyword to declare a multi-line variable, like this:
define ANNOUNCE_BODY
Version $(VERSION) of $(PACKAGE_NAME) has been released.
It can be downloaded from $(DOWNLOAD_URL).
etc, etc.
endef
The tricky part is getting your multi-line variable back out of the makefile. If you just do the obvious thing of using "echo $(ANNOUNCE_BODY)", you'll see the result that others have posted here -- the shell tries to handle the second and subsequent lines of the variable as commands themselves.
However, you can export the variable value as-is to the shell as an environment variable, and then reference it from the shell as an environment variable (NOT a make variable). For example:
export ANNOUNCE_BODY
all:
#echo "$$ANNOUNCE_BODY"
Note the use of $$ANNOUNCE_BODY, indicating a shell environment variable reference, rather than $(ANNOUNCE_BODY), which would be a regular make variable reference. Also be sure to use quotes around your variable reference, to make sure that the newlines aren't interpreted by the shell itself.
Of course, this particular trick may be platform and shell sensitive. I tested it on Ubuntu Linux with GNU bash 3.2.13; YMMV.
Another approach to 'getting your multi-line variable back out of the makefile' (noted by Eric Melski as 'the tricky part'), is to plan to use the subst function to replace the newlines introduced with define in your multi-line string with \n. Then use -e with echo to interpret them. You may need to set the .SHELL=bash to get an echo that does this.
An advantage of this approach is that you also put other such escape characters into your text and have them respected.
This sort of synthesizes all the approaches mentioned so far...
You wind up with:
define newline
endef
define ANNOUNCE_BODY
As of $(shell date), version $(VERSION) of $(PACKAGE_NAME) has been released.
It can be downloaded from $(DOWNLOAD_URL).
endef
someTarget:
echo -e '$(subst $(newline),\n,${ANNOUNCE_BODY})'
Note the single quotes on the final echo are crucial.
Assuming you only want to print the content of your variable on standard output, there is another solution :
do-echo:
$(info $(YOUR_MULTILINE_VAR))
Yes. You escape the newlines with \:
VARIABLE="\
THIS IS A VERY LONG\
TEXT STRING IN A MAKE VARIABLE"
update
Ah, you want the newlines? Then no, I don't think there's any way in vanilla Make. However, you can always use a here-document in the command part
[This does not work, see comment from MadScientist]
foo:
echo <<EOF
Here is a multiple line text
with embedded newlines.
EOF
Not completely related to the OP, but hopefully this will help someone in future.
(as this question is the one that comes up most in google searches).
In my Makefile, I wanted to pass the contents of a file, to a docker build command,
after much consternation, I decided to:
base64 encode the contents in the Makefile (so that I could have a single line and pass them as a docker build arg...)
base64 decode the contents in the Dockerfile (and write them to a file)
see example below.
nb: In my particular case, I wanted to pass an ssh key, during the image build, using the example from https://vsupalov.com/build-docker-image-clone-private-repo-ssh-key/ (using a multi stage docker build to clone a git repo, then drop the ssh key from the final image in the 2nd stage of the build)
Makefile
...
MY_VAR_ENCODED=$(shell cat /path/to/my/file | base64)
my-build:
#docker build \
--build-arg MY_VAR_ENCODED="$(MY_VAR_ENCODED)" \
--no-cache \
-t my-docker:build .
...
Dockerfile
...
ARG MY_VAR_ENCODED
RUN mkdir /root/.ssh/ && \
echo "${MY_VAR_ENCODED}" | base64 -d > /path/to/my/file/in/container
...
Why don't you make use of the \n character in your string to define the end-of-line? Also add the extra backslash to add it over multiple lines.
ANNOUNCE_BODY=" \n\
Version $(VERSION) of $(PACKAGE_NAME) has been released \n\
\n\
It can be downloaded from $(DOWNLOAD_URL) \n\
\n\
etc, etc"
Just a postscript to Eric Melski's answer: You can include the output of commands in the text, but you must use the Makefile syntax "$(shell foo)" rather than the shell syntax "$(foo)". For example:
define ANNOUNCE_BODY
As of $(shell date), version $(VERSION) of $(PACKAGE_NAME) has been released.
It can be downloaded from $(DOWNLOAD_URL).
endef
You should use "define/endef" Make construct:
define ANNOUNCE_BODY
Version $(VERSION) of $(PACKAGE_NAME) has been released.
It can be downloaded from $(DOWNLOAD_URL).
etc, etc.
endef
Then you should pass value of this variable to shell command. But, if you do this using Make variable substitution, it will cause command to split into multiple:
ANNOUNCE.txt:
echo $(ANNOUNCE_BODY) > $# # doesn't work
Qouting won't help either.
The best way to pass value is to pass it via environment variable:
ANNOUNCE.txt: export ANNOUNCE_BODY:=$(ANNOUNCE_BODY)
ANNOUNCE.txt:
echo "$${ANNOUNCE_BODY}" > $#
Notice:
Variable is exported for this particular target, so that you can reuse that environment will not get polluted much;
Use environment variable (double qoutes and curly brackets around variable name);
Use of quotes around variable. Without them newlines will be lost and all text will appear on one line.
This doesn't give a here document, but it does display a multi-line message in a way that's suitable for pipes.
=====
MSG = this is a\\n\
multi-line\\n\
message
method1:
#$(SHELL) -c "echo '$(MSG)'" | sed -e 's/^ //'
=====
You can also use Gnu's callable macros:
=====
MSG = this is a\\n\
multi-line\\n\
message
method1:
#echo "Method 1:"
#$(SHELL) -c "echo '$(MSG)'" | sed -e 's/^ //'
#echo "---"
SHOW = $(SHELL) -c "echo '$1'" | sed -e 's/^ //'
method2:
#echo "Method 2:"
#$(call SHOW,$(MSG))
#echo "---"
=====
Here's the output:
=====
$ make method1 method2
Method 1:
this is a
multi-line
message
---
Method 2:
this is a
multi-line
message
---
$
=====
With GNU Make 3.82 and above, the .ONESHELL option is your friend when it comes to multiline shell snippets. Putting together hints from other answers, I get:
VERSION = 1.2.3
PACKAGE_NAME = foo-bar
DOWNLOAD_URL = $(PACKAGE_NAME).somewhere.net
define nwln
endef
define ANNOUNCE_BODY
Version $(VERSION) of $(PACKAGE_NAME) has been released.
It can be downloaded from $(DOWNLOAD_URL).
etc, etc.
endef
.ONESHELL:
# mind the *leading* <tab> character
version:
#printf "$(subst $(nwln),\n,$(ANNOUNCE_BODY))"
Make sure, when copying and pasting the above example into your editor, that any <tab> characters are preserved, else the version target will break!
Note that .ONESHELL will cause all targets in the Makefile to use a single shell for all their commands.
GNU `make' manual, 6.8: Defining Multi-Line Variables
In the spirit of .ONESHELL, it's possible to get pretty close in .ONESHELL challenged environments:
define _oneshell_newline_
endef
define oneshell
#eval "$$(printf '%s\n' '$(strip \
$(subst $(_oneshell_newline_),\n, \
$(subst \,\/, \
$(subst /,//, \
$(subst ','"'"',$(1))))))' | \
sed -e 's,\\n,\n,g' -e 's,\\/,\\,g' -e 's,//,/,g')"
endef
An example of use would be something like this:
define TEST
printf '>\n%s\n' "Hello
World\n/$$$$/"
endef
all:
$(call oneshell,$(TEST))
That shows the output (assuming pid 27801):
>
Hello
World\n/27801/
This approach does allow for some extra functionality:
define oneshell
#eval "set -eux ; $$(printf '%s\n' '$(strip \
$(subst $(_oneshell_newline_),\n, \
$(subst \,\/, \
$(subst /,//, \
$(subst ','"'"',$(1))))))' | \
sed -e 's,\\n,\n,g' -e 's,\\/,\\,g' -e 's,//,/,g')"
endef
These shell options will:
Print each command as it is executed
Exit on the first failed command
Treat use of undefined shell variables as an error
Other interesting possibilities will likely suggest themselves.
I like alhadis's answer best. But to keep columnar formatting, add one more thing.
SYNOPSIS := :: Synopsis: Makefile\
| ::\
| :: Usage:\
| :: make .......... : generates this message\
| :: make synopsis . : generates this message\
| :: make clean .... : eliminate unwanted intermediates and targets\
| :: make all ...... : compile entire system from ground-up\
endef
Outputs:
:: Synopsis: Makefile
::
:: Usage:
:: make .......... : generates this message
:: make synopsis . : generates this message
:: make clean .... : eliminate unwanted intermediates and targets
:: make all ...... : compile entire system from ground-up
Not really a helpful answer, but just to indicate that 'define' does not work as answered by Ax (did not fit in a comment):
VERSION=4.3.1
PACKAGE_NAME=foobar
DOWNLOAD_URL=www.foobar.com
define ANNOUNCE_BODY
Version $(VERSION) of $(PACKAGE_NAME) has been released
It can be downloaded from $(DOWNLOAD_URL)
etc, etc
endef
all:
#echo $(ANNOUNCE_BODY)
It gives an error that the command 'It' cannot be found, so it tries to interpret the second line of ANNOUNCE BODY as a command.
It worked for me:
ANNOUNCE_BODY="first line\\nsecond line"
all:
#echo -e $(ANNOUNCE_BODY)
GNU Makefile can do things like the following. It is ugly, and I won't say you should do it, but I do in certain situations.
PROFILE = \
\#!/bin/sh.exe\n\
\#\n\
\# A MinGW equivalent for .bash_profile on Linux. In MinGW/MSYS, the file\n\
\# is actually named .profile, not .bash_profile.\n\
\#\n\
\# Get the aliases and functions\n\
\#\n\
if [ -f \$${HOME}/.bashrc ]\n\
then\n\
. \$${HOME}/.bashrc\n\
fi\n\
\n\
export CVS_RSH="ssh"\n
#
.profile:
echo -e "$(PROFILE)" | sed -e 's/^[ ]//' >.profile
make .profile creates a .profile file if one does not exist.
This solution was used where the application will only use GNU Makefile in a POSIX shell environment. The project is not an open source project where platform compatibility is an issue.
The goal was to create a Makefile that facilitates both setup and use of a particular kind of workspace. The Makefile brings along with it various simple resources without requiring things like another special archive, etc. It is, in a sense, a shell archive. A procedure can then say things like drop this Makefile in the folder to work in. Set up your workspace enter make workspace, then to do blah, enter make blah, etc.
What can get tricky is figuring out what to shell quote. The above does the job and is close to the idea of specifying a here document in the Makefile. Whether it is a good idea for general use is a whole other issue.
I believe the safest answer for cross-platform use would be to use one echo per line:
ANNOUNCE.txt:
rm -f $#
echo "Version $(VERSION) of $(PACKAGE_NAME) has been released" > $#
echo "" >> $#
echo "It can be downloaded from $(DOWNLOAD_URL)" >> $#
echo >> $#
echo etc, etc" >> $#
This avoids making any assumptions of on the version of echo available.
Use string substitution:
VERSION := 1.1.1
PACKAGE_NAME := Foo Bar
DOWNLOAD_URL := https://go.get/some/thing.tar.gz
ANNOUNCE_BODY := Version $(VERSION) of $(PACKAGE_NAME) has been released. \
| \
| It can be downloaded from $(DOWNLOAD_URL) \
| \
| etc, etc
Then in your recipe, put
#echo $(subst | ,$$'\n',$(ANNOUNCE_BODY))
This works because Make is substituting all occurrences of | (note the space) and swapping it with a newline character ($$'\n'). You can think of the equivalent shell-script invocations as being something like this:
Before:
$ echo "Version 1.1.1 of Foo Bar has been released. | | It can be downloaded from https://go.get/some/thing.tar.gz | | etc, etc"
After:
$ echo "Version 1.1.1 of Foo Bar has been released.
>
> It can be downloaded from https://go.get/some/thing.tar.gz
>
> etc, etc"
I'm not sure if $'\n' is available on non-POSIX systems, but if you can gain access to a single newline character (even by reading a string from an external file), the underlying principle is the same.
If you have many messages like this, you can reduce noise by using a macro:
print = $(subst | ,$$'\n',$(1))
Where you'd invoke it like this:
#$(call print,$(ANNOUNCE_BODY))
Hope this helps somebody. =)
As an alternative you can use the printf command. This is helpful on OSX or other platforms with less features.
To simply output a multiline message:
all:
#printf '%s\n' \
'Version $(VERSION) has been released' \
'' \
'You can download from URL $(URL)'
If you are trying to pass the string as an arg to another program, you can do so like this:
all:
/some/command "`printf '%s\n' 'Version $(VERSION) has been released' '' 'You can download from URL $(URL)'`"