# [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE 5 messages from 2006-04-15 to 2006-04-16. Participants: Johannes Schindelin, Junio C Hamano. Thread: https://gitlist.dev/t/3879 ## Johannes Schindelin, 2006-04-15 13:16 Subject: [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE Message-ID: URL: https://gitlist.dev/e/Pine.LNX.4.63.0604151516150.6563%40wbgn013.biozentrum.uni-wuerzburg.de ``` This helps debugging tremendously. Signed-off-by: Johannes Schindelin --- pager.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) a91a9371e117555a03cfe7d24515787fb13005b6 diff --git a/pager.c b/pager.c index 1364e15..1136adf 100644 --- a/pager.c +++ b/pager.c @@ -5,9 +5,8 @@ #include "cache.h" * something different on Windows, for example. */ -static void run_pager(void) +static void run_pager(const char *prog) { - const char *prog = getenv("PAGER"); if (!prog) prog = "less"; setenv("LESS", "-S", 0); @@ -16,10 +15,11 @@ static void run_pager(void) void setup_pager(void) { + const char *prog = getenv("PAGER"); pid_t pid; int fd[2]; - if (!isatty(1)) + if (!isatty(1) || (prog != NULL && !strcmp(prog, "NONE"))) return; if (pipe(fd) < 0) return; @@ -43,6 +43,6 @@ void setup_pager(void) close(fd[0]); close(fd[1]); - run_pager(); + run_pager(prog); exit(255); } -- 1.3.0.rc4.g667c ``` ## Junio C Hamano, 2006-04-15 20:50 Subject: Re: [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE Message-ID: <7vwtdqef6u.fsf@assigned-by-dhcp.cox.net> URL: https://gitlist.dev/e/7vwtdqef6u.fsf%40assigned-by-dhcp.cox.net In-Reply-To: ``` Johannes Schindelin writes: > This helps debugging tremendously. > > Signed-off-by: Johannes Schindelin I like what this wants to do. I am not so sure PAGER=NONE is a good convention, however. ``` ## Johannes Schindelin, 2006-04-16 02:01 Subject: Re: [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE Message-ID: URL: https://gitlist.dev/e/Pine.LNX.4.63.0604160357460.31461%40wbgn013.biozentrum.uni-wuerzburg.de In-Reply-To: <7vwtdqef6u.fsf@assigned-by-dhcp.cox.net> ``` Hi, On Sat, 15 Apr 2006, Junio C Hamano wrote: > Johannes Schindelin writes: > > > This helps debugging tremendously. > > > > Signed-off-by: Johannes Schindelin > > I like what this wants to do. I am not so sure PAGER=NONE is a > good convention, however. I am sure it is not. One solution would be to introduce yet another command line option "--no-pager", but I find that ugly. Another solution would be to check if the environment variable NO_PAGER is set. Wishes? Ciao, Dscho ``` ## Junio C Hamano, 2006-04-16 02:20 Subject: Re: [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE Message-ID: <7v4q0udzwg.fsf@assigned-by-dhcp.cox.net> URL: https://gitlist.dev/e/7v4q0udzwg.fsf%40assigned-by-dhcp.cox.net In-Reply-To: ``` Johannes Schindelin writes: > Hi, > > On Sat, 15 Apr 2006, Junio C Hamano wrote: > >> Johannes Schindelin writes: >> >> > This helps debugging tremendously. >> > >> > Signed-off-by: Johannes Schindelin >> >> I like what this wants to do. I am not so sure PAGER=NONE is a >> good convention, however. > > I am sure it is not. > > One solution would be to introduce yet another command line option > "--no-pager", but I find that ugly. > > Another solution would be to check if the environment variable NO_PAGER is > set. > > Wishes? Honestly, undecided. Not that I think people would do PAGER=NONE to mean a program /usr/bin/NONE. Right now, the following does not say anything: $ PAGER= git log but I do not think that is a reasonably behaviour, either. So detecting PAGER is set to an empty string (not "nonexistence" - the current behaviour of defaulting to "less" in such a case is reasonable) is probably a better alternative. A somewhat related topic; I often set PAGER=cat when I do not want the --[More]-- prompt and I thing many Emacs users do this. It might also be good to detect it and omit piping in such a case, but that is independent, so if you are going to do this as well, please make it a separate patch. ``` ## Johannes Schindelin, 2006-04-16 02:44 Subject: Re: [RFC/PATCH] pager: do not fork a pager if environment variable PAGER is set to NONE Message-ID: URL: https://gitlist.dev/e/Pine.LNX.4.63.0604160438370.32484%40wbgn013.biozentrum.uni-wuerzburg.de In-Reply-To: <7v4q0udzwg.fsf@assigned-by-dhcp.cox.net> ``` Hi, On Sat, 15 Apr 2006, Junio C Hamano wrote: > A somewhat related topic; I often set PAGER=cat when I do not > want the --[More]-- prompt and I thing many Emacs users do this. > It might also be good to detect it and omit piping in such a > case, but that is independent, so if you are going to do this as > well, please make it a separate patch. I was not quite sure if PAGER=cat could be taken as "user does not want any pager to be fork()ed", but you are probably right: PAGER=cat means that stdout is forwarded to stdout, i.e. we are better off not fork()ing and calling "cat": --- [PATCH] pager: do not fork a pager if PAGER=cat This helps debugging tremendously. Signed-off-by: Johannes Schindelin --- pager.c | 8 ++++---- 1 files changed, 4 insertions(+), 4 deletions(-) 4a617a436bba9288cec5d3918d02c5b0e652df98 diff --git a/pager.c b/pager.c index 1364e15..86e93b3 100644 --- a/pager.c +++ b/pager.c @@ -5,9 +5,8 @@ #include "cache.h" * something different on Windows, for example. */ -static void run_pager(void) +static void run_pager(const char *prog) { - const char *prog = getenv("PAGER"); if (!prog) prog = "less"; setenv("LESS", "-S", 0); @@ -16,10 +15,11 @@ static void run_pager(void) void setup_pager(void) { + const char *prog = getenv("PAGER"); pid_t pid; int fd[2]; - if (!isatty(1)) + if (!isatty(1) || (prog != NULL && !strcmp(prog, "cat"))) return; if (pipe(fd) < 0) return; @@ -43,6 +43,6 @@ void setup_pager(void) close(fd[0]); close(fd[1]); - run_pager(); + run_pager(prog); exit(255); } -- 1.3.0.rc4.gb6b20-dirty ```