Why would /etc/passwd be used every time someone executes `ls -l` command?
Read from APUE, just feel curious:
The password file is used every time a user logs in to a
UNIX system and every time someone executes anls -lcommand.
ls passwd
edited 1 hour ago
Olorin
3,8681721
asked 2 hours ago
RickRick
1335
add a comment |
Read from APUE, just feel curious:
The password file is used every time a user logs in to a
UNIX system and every time someone executes anls -lcommand.
ls passwd
edited 1 hour ago
Olorin
3,8681721
asked 2 hours ago
RickRick
1335
FYI I trystrace ls -llater on, I see aopenat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4statement.
– Rick
11 mins ago
add a comment |
Read from APUE, just feel curious:
The password file is used every time a user logs in to a
UNIX system and every time someone executes anls -lcommand.
ls passwd
edited 1 hour ago
Olorin
3,8681721
asked 2 hours ago
RickRick
1335
Read from APUE, just feel curious:
The password file is used every time a user logs in to a
UNIX system and every time someone executes anls -lcommand.
ls passwd
ls passwd
edited 1 hour ago
Olorin
3,8681721
asked 2 hours ago
RickRick
1335
edited 1 hour ago
Olorin
3,8681721
asked 2 hours ago
RickRick
1335
edited 1 hour ago
Olorin
3,8681721
edited 1 hour ago
Olorin
3,8681721
edited 1 hour ago
Olorin
3,8681721
3,8681721
asked 2 hours ago
RickRick
1335
asked 2 hours ago
RickRick
1335
asked 2 hours ago
RickRick
1335
1335
FYI I trystrace ls -llater on, I see aopenat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4statement.
– Rick
11 mins ago
add a comment |
FYI I trystrace ls -llater on, I see aopenat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4statement.
– Rick
11 mins ago
FYI I try
strace ls -l later on, I see a openat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4 statement.– Rick
11 mins ago
FYI I try
strace ls -l later on, I see a openat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4 statement.– Rick
11 mins ago
add a comment |
1 Answer
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The file-system directly associates the numerical UID (User ID) and GID (Group ID) values with the file, not the user name and group name (which are strings). So the ls -l command (and any other command that displays the user and group owner of a file) need to get the user and group names from somewhere. The /etc/passwd file is one such source (probably the original and most common source). The manual bears this out - from PASSWD (5) (i.e. the man page for the /etc/passwd file):
many utilities, like ls(1) use it to map user IDs to usernames
answered 2 hours ago
igaligal
5,3711234
add a comment |
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1 Answer
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active
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1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
The file-system directly associates the numerical UID (User ID) and GID (Group ID) values with the file, not the user name and group name (which are strings). So the ls -l command (and any other command that displays the user and group owner of a file) need to get the user and group names from somewhere. The /etc/passwd file is one such source (probably the original and most common source). The manual bears this out - from PASSWD (5) (i.e. the man page for the /etc/passwd file):
many utilities, like ls(1) use it to map user IDs to usernames
answered 2 hours ago
igaligal
5,3711234
add a comment |
The file-system directly associates the numerical UID (User ID) and GID (Group ID) values with the file, not the user name and group name (which are strings). So the ls -l command (and any other command that displays the user and group owner of a file) need to get the user and group names from somewhere. The /etc/passwd file is one such source (probably the original and most common source). The manual bears this out - from PASSWD (5) (i.e. the man page for the /etc/passwd file):
many utilities, like ls(1) use it to map user IDs to usernames
answered 2 hours ago
igaligal
5,3711234
add a comment |
The file-system directly associates the numerical UID (User ID) and GID (Group ID) values with the file, not the user name and group name (which are strings). So the ls -l command (and any other command that displays the user and group owner of a file) need to get the user and group names from somewhere. The /etc/passwd file is one such source (probably the original and most common source). The manual bears this out - from PASSWD (5) (i.e. the man page for the /etc/passwd file):
many utilities, like ls(1) use it to map user IDs to usernames
answered 2 hours ago
igaligal
5,3711234
The file-system directly associates the numerical UID (User ID) and GID (Group ID) values with the file, not the user name and group name (which are strings). So the ls -l command (and any other command that displays the user and group owner of a file) need to get the user and group names from somewhere. The /etc/passwd file is one such source (probably the original and most common source). The manual bears this out - from PASSWD (5) (i.e. the man page for the /etc/passwd file):
many utilities, like ls(1) use it to map user IDs to usernames
answered 2 hours ago
igaligal
5,3711234
edited 2 hours ago
answered 2 hours ago
igaligal
5,3711234
answered 2 hours ago
igaligal
5,3711234
answered 2 hours ago
igaligal
5,3711234
5,3711234
add a comment |
add a comment |
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FYI I try
strace ls -llater on, I see aopenat(AT_FDCWD, "/etc/passwd", O_RDONLY|O_CLOEXEC) = 4statement.– Rick
11 mins ago