How to collect output of several commands into one file in CMake? - cmake

Question

I am trying to collect Git information into file and am doing
execute_process(
COMMAND git log -1 --format=full && echo "Modified files:" && git ls-files -m
OUTPUT_FILE "git_log"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
or
execute_process(
COMMAND git log -1 --format=full
COMMAND echo "Modified files:"
COMMAND git ls-files -m
OUTPUT_FILE "git_log"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
And in both cases don't see full content. In first case I see empty file and in second -- only output of last command.
How to gather all in one file?

Answer 1

in first case I see empty file
Sure - no shell is used, and && is invalid argument to git, the command fails. See documentation No intermediate shell is used, so shell operators such as > are treated as normal arguments.
in second -- only output of last command.
Sure - see documentation Commands are executed concurrently as a pipeline, with the standard output of each process piped to the standard input of the next. git ... | echo ... | git ... will only output the last one - git and echo ignore standard input.
execute_process(
COMMAND sh -c "
git log -1 --format=full &&
echo \"Modified files:\" &&
git ls-files -m"
OUTPUT_FILE "git_log1"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
or
execute_process(
COMMAND git log -1 --format=full
OUTPUT_FILE "git_log1"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
execute_process(
COMMAND echo ...
OUTPUT_FILE "git_log2"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
execute_process(
COMMAND git ...
OUTPUT_FILE "git_log3"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)
execute_process(
COMMAND ${CMAKE_COMMAND} -E cat git_log1 git_log2 git_log3
OUTPUT_FILE "git_log"
WORKING_DIRECTORY ${PROJECT_SOURCE_DIR}
)