Commit b3275838 authored by Matthieu Moy's avatar Matthieu Moy Committed by Junio C Hamano

pager: remove 'S' from $LESS by default

By default, Git used to set $LESS to -FRSX if $LESS was not set by
the user. The FRX flags actually make sense for Git (F and X because
sometimes the output Git pipes to less is short, and R because Git
pipes colored output). The S flag (chop long lines), on the other
hand, is not related to Git and is a matter of user preference. Git
should not decide for the user to change LESS's default.

More specifically, the S flag harms users who review untrusted code
within a pager, since a patch looking like:

    -old code;
    +new good code; [... lots of tabs ...] malicious code;

would appear identical to:

    -old code;
    +new good code;

Users who prefer the old behavior can still set the $LESS environment
variable to -FRSX explicitly, or set core.pager to 'less -S'.

The documentation in config.txt is made a bit longer to keep both an
example setting the 'S' flag (needed to recover the old behavior)
and an example showing how to unset a flag set by Git.
Signed-off-by: default avatarMatthieu Moy <>
Signed-off-by: default avatarJunio C Hamano <>
parent d8779e1e
......@@ -558,14 +558,19 @@ core.pager::
configuration, then `$PAGER`, and then the default chosen at
compile time (usually 'less').
When the `LESS` environment variable is unset, Git sets it to `FRSX`
When the `LESS` environment variable is unset, Git sets it to `FRX`
(if `LESS` environment variable is set, Git does not change it at
all). If you want to selectively override Git's default setting
for `LESS`, you can set `core.pager` to e.g. `less -+S`. This will
for `LESS`, you can set `core.pager` to e.g. `less -S`. This will
be passed to the shell by Git, which will translate the final
command to `LESS=FRSX less -+S`. The environment tells the command
to set the `S` option to chop long lines but the command line
resets it to the default to fold long lines.
command to `LESS=FRX less -S`. The environment does not set the
`S` option but the command line does, instructing less to truncate
long lines. Similarly, setting `core.pager` to `less -+F` will
deactivate the `F` option specified by the environment from the
command-line, deactivating the "quit if one screen" behavior of
`less`. One can specifically activate some flags for particular
commands: for example, setting `pager.blame` to `less -S` enables
line truncation only for `git blame`.
Likewise, when the `LV` environment variable is unset, Git sets it
to `-c`. You can override this setting by exporting `LV` with
......@@ -160,7 +160,7 @@ git_pager() {
: ${LESS=-FRX}
: ${LV=-c}
export LESS LV
......@@ -85,7 +85,7 @@ void setup_pager(void)
int i = 0;
if (!getenv("LESS"))
env[i++] = "LESS=FRSX";
env[i++] = "LESS=FRX";
if (!getenv("LV"))
env[i++] = "LV=-c";
env[i] = NULL;
......@@ -116,7 +116,7 @@ sub run_pager {
open STDIN, '<&', $rfd or fatal "Can't redirect stdin: $!";
$ENV{LESS} ||= 'FRSX';
$ENV{LESS} ||= 'FRX';
$ENV{LV} ||= '-c';
exec $pager or fatal "Can't run pager: $! ($pager)";
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