Does cd . have use?
One of the tutorials I've been following briefly stated that cd . has no use. When trying to replicate issue shown by OP in Symbolic link recursion - what makes it “reset”?, I also tried cd ., which showed the same effect OP described (growing $PWD variable), which can be countered with cd -P.
This makes me wonder, is there any case where one does in fact would want to use cd . ?
cd-command
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
add a comment |
One of the tutorials I've been following briefly stated that cd . has no use. When trying to replicate issue shown by OP in Symbolic link recursion - what makes it “reset”?, I also tried cd ., which showed the same effect OP described (growing $PWD variable), which can be countered with cd -P.
This makes me wonder, is there any case where one does in fact would want to use cd . ?
cd-command
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
add a comment |
One of the tutorials I've been following briefly stated that cd . has no use. When trying to replicate issue shown by OP in Symbolic link recursion - what makes it “reset”?, I also tried cd ., which showed the same effect OP described (growing $PWD variable), which can be countered with cd -P.
This makes me wonder, is there any case where one does in fact would want to use cd . ?
cd-command
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
One of the tutorials I've been following briefly stated that cd . has no use. When trying to replicate issue shown by OP in Symbolic link recursion - what makes it “reset”?, I also tried cd ., which showed the same effect OP described (growing $PWD variable), which can be countered with cd -P.
This makes me wonder, is there any case where one does in fact would want to use cd . ?
cd-command
cd-command
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
asked 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
8,70912355
add a comment |
add a comment |
2 Answers
2
active
oldest
votes
The path of directory could have changed since the last executed command and without cd . bash and ksh93 shells will rely on logical working directory described in the linked post in the question; so calling cd . which makes the shell issue getcwd() syscall, will ensure your current path is still valid.
Steps to reproduce in bash:
- in terminal tab issue
mkdir ./dir_no_1; cd ./dir_no_1
- in different terminal tab issue
mv dir_no_1 dir_no_2
- issue in first terminal tab
echo $PWDandpwd. Notice that the directory has been externally renamed, shell's environment has not been updated. - issue
cd .; pwd; echo $PWD. Notice the value will be updated.
ksh93, however, does not update the environment information, so cd . in ksh93 may in fact be useless. In /bin/dash on Ubuntu and other Debian based systems, cd . returns dash: 3: cd: can't cd to . error, however cd -P . works ( unlike in ksh93 ).
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
add a comment |
I think this is overthinking the problem. cd . may not be something that one would manually run in the usual course of things, but it definitely is something that can come up in programmatic execution (think of any situation where you might cd to the directory containing a file, whose path is supplied by the user). Therefore, it doesn't have to have some specific use: as long as it fulfills the usual semantics of cd <some-path>, it is useful.
answered 1 hour ago
OlorinOlorin
1,799313
Agreed,.should be treated as a valid path specified bycdsyntax just fine.
– Sergiy Kolodyazhnyy
1 hour ago
add a comment |
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
The path of directory could have changed since the last executed command and without cd . bash and ksh93 shells will rely on logical working directory described in the linked post in the question; so calling cd . which makes the shell issue getcwd() syscall, will ensure your current path is still valid.
Steps to reproduce in bash:
- in terminal tab issue
mkdir ./dir_no_1; cd ./dir_no_1
- in different terminal tab issue
mv dir_no_1 dir_no_2
- issue in first terminal tab
echo $PWDandpwd. Notice that the directory has been externally renamed, shell's environment has not been updated. - issue
cd .; pwd; echo $PWD. Notice the value will be updated.
ksh93, however, does not update the environment information, so cd . in ksh93 may in fact be useless. In /bin/dash on Ubuntu and other Debian based systems, cd . returns dash: 3: cd: can't cd to . error, however cd -P . works ( unlike in ksh93 ).
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
add a comment |
The path of directory could have changed since the last executed command and without cd . bash and ksh93 shells will rely on logical working directory described in the linked post in the question; so calling cd . which makes the shell issue getcwd() syscall, will ensure your current path is still valid.
Steps to reproduce in bash:
- in terminal tab issue
mkdir ./dir_no_1; cd ./dir_no_1
- in different terminal tab issue
mv dir_no_1 dir_no_2
- issue in first terminal tab
echo $PWDandpwd. Notice that the directory has been externally renamed, shell's environment has not been updated. - issue
cd .; pwd; echo $PWD. Notice the value will be updated.
ksh93, however, does not update the environment information, so cd . in ksh93 may in fact be useless. In /bin/dash on Ubuntu and other Debian based systems, cd . returns dash: 3: cd: can't cd to . error, however cd -P . works ( unlike in ksh93 ).
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
add a comment |
The path of directory could have changed since the last executed command and without cd . bash and ksh93 shells will rely on logical working directory described in the linked post in the question; so calling cd . which makes the shell issue getcwd() syscall, will ensure your current path is still valid.
Steps to reproduce in bash:
- in terminal tab issue
mkdir ./dir_no_1; cd ./dir_no_1
- in different terminal tab issue
mv dir_no_1 dir_no_2
- issue in first terminal tab
echo $PWDandpwd. Notice that the directory has been externally renamed, shell's environment has not been updated. - issue
cd .; pwd; echo $PWD. Notice the value will be updated.
ksh93, however, does not update the environment information, so cd . in ksh93 may in fact be useless. In /bin/dash on Ubuntu and other Debian based systems, cd . returns dash: 3: cd: can't cd to . error, however cd -P . works ( unlike in ksh93 ).
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
The path of directory could have changed since the last executed command and without cd . bash and ksh93 shells will rely on logical working directory described in the linked post in the question; so calling cd . which makes the shell issue getcwd() syscall, will ensure your current path is still valid.
Steps to reproduce in bash:
- in terminal tab issue
mkdir ./dir_no_1; cd ./dir_no_1
- in different terminal tab issue
mv dir_no_1 dir_no_2
- issue in first terminal tab
echo $PWDandpwd. Notice that the directory has been externally renamed, shell's environment has not been updated. - issue
cd .; pwd; echo $PWD. Notice the value will be updated.
ksh93, however, does not update the environment information, so cd . in ksh93 may in fact be useless. In /bin/dash on Ubuntu and other Debian based systems, cd . returns dash: 3: cd: can't cd to . error, however cd -P . works ( unlike in ksh93 ).
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
answered 2 hours ago
Sergiy KolodyazhnyySergiy Kolodyazhnyy
8,70912355
8,70912355
add a comment |
add a comment |
I think this is overthinking the problem. cd . may not be something that one would manually run in the usual course of things, but it definitely is something that can come up in programmatic execution (think of any situation where you might cd to the directory containing a file, whose path is supplied by the user). Therefore, it doesn't have to have some specific use: as long as it fulfills the usual semantics of cd <some-path>, it is useful.
answered 1 hour ago
OlorinOlorin
1,799313
Agreed,.should be treated as a valid path specified bycdsyntax just fine.
– Sergiy Kolodyazhnyy
1 hour ago
add a comment |
I think this is overthinking the problem. cd . may not be something that one would manually run in the usual course of things, but it definitely is something that can come up in programmatic execution (think of any situation where you might cd to the directory containing a file, whose path is supplied by the user). Therefore, it doesn't have to have some specific use: as long as it fulfills the usual semantics of cd <some-path>, it is useful.
answered 1 hour ago
OlorinOlorin
1,799313
Agreed,.should be treated as a valid path specified bycdsyntax just fine.
– Sergiy Kolodyazhnyy
1 hour ago
add a comment |
I think this is overthinking the problem. cd . may not be something that one would manually run in the usual course of things, but it definitely is something that can come up in programmatic execution (think of any situation where you might cd to the directory containing a file, whose path is supplied by the user). Therefore, it doesn't have to have some specific use: as long as it fulfills the usual semantics of cd <some-path>, it is useful.
answered 1 hour ago
OlorinOlorin
1,799313
I think this is overthinking the problem. cd . may not be something that one would manually run in the usual course of things, but it definitely is something that can come up in programmatic execution (think of any situation where you might cd to the directory containing a file, whose path is supplied by the user). Therefore, it doesn't have to have some specific use: as long as it fulfills the usual semantics of cd <some-path>, it is useful.
answered 1 hour ago
OlorinOlorin
1,799313
answered 1 hour ago
OlorinOlorin
1,799313
answered 1 hour ago
OlorinOlorin
1,799313
answered 1 hour ago
OlorinOlorin
1,799313
1,799313
Agreed,.should be treated as a valid path specified bycdsyntax just fine.
– Sergiy Kolodyazhnyy
1 hour ago
add a comment |
Agreed,.should be treated as a valid path specified bycdsyntax just fine.
– Sergiy Kolodyazhnyy
1 hour ago
Agreed,
. should be treated as a valid path specified by cd syntax just fine.– Sergiy Kolodyazhnyy
1 hour ago
Agreed,
. should be treated as a valid path specified by cd syntax just fine.– Sergiy Kolodyazhnyy
1 hour ago
add a comment |
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