On 02.09.2021 21:49, Mortimer Cladwell wrote: > Hi, > > Consider my file test.scm: > > (define (main args) > (let* ((myvar (string-append "export > GUILE_LOAD_PATH=/some/random/text:$GUILE_LOAD_PATH")) > (statement1 (system (string-append "echo " myvar " >> > $HOME/.bashrc"))) > (statement2 (system myvar))) > (write myvar))) > > At the terminal: > > mbc@HP8300:~/temp$ echo $GUILE_LOAD_PATH > /home/mbc/.guix-profile/share/guile/site/3.0 > > mbc@HP8300:~/temp$ guile -e main -s test.scm > "export GUILE_LOAD_PATH=/some/random/text:$GUILE_LOAD_PATH" > > mbc@HP8300:~/temp$ echo $GUILE_LOAD_PATH > /home/mbc/.guix-profile/share/guile/site/3.0 > > At the end of .bashrc I see the last line is: > > export > GUILE_LOAD_PATH=/some/random/text:/home/mbc/.guix-profile/share/guile/site/3.0 > > If I close and reopen the terminal and: > > mbc@HP8300:~$ echo $GUILE_LOAD_PATH > /some/random/text:/home/mbc/.guix-profile/share/guile/site/3.0 > > So statement1 works as expected, modifying .bashrc which is then effective > in modifying GUILE_LOAD_PATH on future invocations of terminal. > > statement2 is an attempt to modify the current running environment, but > fails. > Note that if I paste export > GUILE_LOAD_PATH=/some/random/text:$GUILE_LOAD_PATH directly into the > terminal, that successfully modifies the variable. > > Why does (system myvar) i.e. (system "export > GUILE_LOAD_PATH=/some/random/text:$GUILE_LOAD_PATH") fail? > Thanks > Mortimer >
Hi Mortimer, The "system" procedure starts a child-process in the operating system. In the Unix process model, the changes to the environment made by a child process do not affect the parent. Note that anything for which you use "system" above can be done directly within Guile by using the appropriate procedures, instead of starting a child process using the system shell. You might want to look for I/O related procedures to figure out how you can append text to an existing file. This might help: https://www.gnu.org/software/guile/manual/html_node/File-Ports.html Setting an environment variable is simple, just use 'setenv': https://www.gnu.org/software/guile/manual/html_node/Runtime-Environment.html Hope that helps. :-) -- Taylan
