Return to Answer

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Notice also that on Linux and possibly Cywin some programs will use xdg-open to open a web browser or simply hard-code a browser to firefox. I have verified that xpdf version 4.05 on my Linux system indeed uses xdg-open using strace -f xpdf sed.pdf. It prints a lot of output and makes xpdf much slower but if you press the link you'll see:

[pid 32675] execve("/usr/bin/xdg-open", ["/usr/bin/xdg-open", "https://en.wikipedia.org/wiki/Qu"...], 0x7ffc65f08a30 /* 65 vars */ <unfinished ...>

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Notice also that on Linux and possibly Cywin some programs will use xdg-open to open a web browser or simply hard-code a browser to firefox. I have verified that xpdf version 4.05 on my Linux system indeed uses xdg-open using strace -f xpdf sed.pdf. It prints a lot of output and makes xpdf much slower but if you press the link you'll see:

[pid 32675] execve("/usr/bin/xdg-open", ["/usr/bin/xdg-open", "https://en.wikipedia.org/wiki/Qu"...], 0x7ffc65f08a30 /* 65 vars */ <unfinished ...>

This part of xpdf manpage is outdated but it's also not so simple:

Clicking on a hyperlink will jump to the link's destination. A link to another PDF document will make xpdf load that document. A ´launch' link to an executable program will display a dialog, and if you click ´ok', execute the program. URL links are opened in a system-dependent way. (On UNIX, Qt uses the $BROWSER environment variable.)

xdg-open indeed uses BROWSER in some places:

$ grep -F '$BROWSER' "$(command -v xdg-open)"
    for browser in $BROWSER; do
    if [ -n "$BROWSER" ]; then
    if [ x"$BROWSER" = x"" ]; then
            BROWSER=x-www-browser:firefox:iceweasel:seamonkey:mozilla:epiphany:konqueror:chromium:chromium-browser:google-chrome:$BROWSER
        BROWSER="$(echo "$BROWSER" | sed -e 's|:xdg-open||g' -e 's|xdg-open:||g')"

But it's a complex script, doing various things on different window and desktop managers. I use i3 and here value of $BROWSERE is not taken into account by xdg-open and it always exits in open_generic().

You can use this to find what will be picked by xdg-open for a given type:

$ XDG_UTILS_DEBUG_LEVEL=10 xdg-mime query default x-scheme-handler/https
Checking /home/ja/.config/mimeapps.list
userapp-Firefox-9Y4BR2.desktop

xpdf manpage could be updated to say that it uses xdg-open, it would clear all confusion.

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Notice also that on Linux and possibly Cywin some programs will use xdg-open to open a web browser or simply hard-code a browser to firefox.

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Notice also that on Linux and possibly Cywin some programs will use xdg-open to open a web browser or simply hard-code a browser to firefox. I have verified that xpdf version 4.05 on my Linux system indeed uses xdg-open using strace -f xpdf sed.pdf. It prints a lot of output and makes xpdf much slower but if you press the link you'll see:

[pid 32675] execve("/usr/bin/xdg-open", ["/usr/bin/xdg-open", "https://en.wikipedia.org/wiki/Qu"...], 0x7ffc65f08a30 /* 65 vars */ <unfinished ...>

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Exported variables are visible to child processes. If you don't need to specifically export a variable for it be used by a child process it means it has already been exported before.

You can verify by starting a new bash session and examining value of BROWSER:

env | grep ^BROWSER=

Notice also that on Linux and possibly Cywin some programs will use xdg-open to open a web browser or simply hard-code a browser to firefox.