LuaPosix: Difference between revisions
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This is a list of the Lua Posix functions. Included is helpful snippets of code. | |||
This is a list of the Lua Posix functions. Included is helpful | |||
Install lua posix. To get this list do: | Install lua posix. To get this list do: | ||
require "posix" | |||
for a in pairs( | for a in pairs(posix) do | ||
print(a) | |||
end | |||
=access= | |||
check real user's permissions for a file | |||
====Synopsis==== | |||
posix.access(''pathname'', ''mode'') | |||
====Description==== | |||
'''access()''' checks whether the calling process can access the file ''pathname''. If pathname is a symbolic link, it is dereferenced. | |||
The mode specifies the accessibility check(s) to be performed, and is either the string '''"f"''', or one or more of '''"r"''', '''"w"''', and '''"x"'''. '''"f"''' tests for the existence of the file. '''"r"''', '''"w"''', and '''"x"''' test whether the file exists and grants read, write, and execute permissions, respectively. | |||
====Return Value==== | |||
On success (all requested permissions granted), zero is returned. On error (at least one char in mode asked for a permission that is denied, or some other error occurred), nil, errorstr and errno is returned. | |||
====Examples==== | |||
status, errstr, errno = posix.access("/etc/passwd", "rw") | |||
if not posix.access("/foo", "f") then | |||
print("/foo does not exist") | |||
end | |||
====References==== | |||
https://man7.org/linux/man-pages/man2/access.2.html | |||
=chdir= | |||
change working directory | |||
====Synopsis==== | |||
posix.chdir(''path'') | |||
====Return Value==== | |||
On success, zero is returned. On error, nil, an error string and errno is returned. | |||
====Examples==== | |||
status, errstr, errno = posix.chdir("/tmp") | |||
if posix.chdir("/tmp") then | |||
print("Changed current working dir to:", posix.getpwd()) | |||
fi | |||
=chmod= | |||
change permissions of a file | |||
====Synopsis==== | |||
posix.chmod(''path'', ''mode'') | |||
====Description==== | |||
The mode of the file given by ''path'' is changed. | |||
Modes are specified in one of the following formats | |||
* "rwxrwxrwx" (i.e "rw-rw-w--") | |||
* "ugoa+-=rwx" (i.e "u+w") | |||
* "+-=rwx" (i.e "+w") | |||
* | |||
== | ====Return Value==== | ||
On success, zero is returned. On error, nil, errstr and errno is returned. | |||
====Examples==== | |||
posix.chmod("/tmp", "a+rwx") | |||
status, errstr = posix.chmod(file, "-w") | |||
if not status then | |||
print(errstr) | |||
fi | |||
=chown= | |||
'''INPUT''' | '''INPUT''' | ||
*Path-location of file or directory | *Path-location of file or directory | ||
Line 60: | Line 86: | ||
--above will give back nil. Since we printed it will also give back the system errors. | --above will give back nil. Since we printed it will also give back the system errors. | ||
==ctermid | =clock_getres= | ||
'''TODO''' | |||
=clock_gettime= | |||
'''TODO''' | |||
=crypt= | |||
password and data encryption | |||
====Synopsis==== | |||
posix.crypt(''string'', ''salt'') | |||
====Return Value==== | |||
On success, zero is returned. On error, nil, an error string and errno is returned. | |||
=ctermid= | |||
'''INPUT''' | '''INPUT''' | ||
*NONE- DISPLAYS the terminal id | *NONE- DISPLAYS the terminal id | ||
Line 68: | Line 110: | ||
print(bar.ctermid()) | print(bar.ctermid()) | ||
==dir== | =dir= | ||
read a directory | |||
''' | |||
====Synopsis==== | |||
''' | posix.dir(''path'') | ||
====Description==== | |||
Reads directory ''path'', and returns a table with all the files. If ''path'' is omitted, current working dir is read. | |||
for a,b in ipairs( | ====Return Value==== | ||
- | '''posix.dir()''' returns a table with all filenames on succes. On error, nil, an error string and errno is returned. | ||
====Examples==== | |||
files, errstr, errno = posix.dir("/var/log") | |||
if files then | |||
for a,b in ipairs(files) do | |||
print(b) | |||
end | |||
else | |||
print(errstr) | |||
end | |||
=dup= | |||
duplicate a file descriptor | |||
====Synopsis==== | |||
posix.dup(''oldfd''[, ''newfd'']) | |||
====Description==== | |||
'''posix.dup()''' creates a copy of the file descriptor ''oldfd''. | |||
''newfd'' will be the copy of ''oldfd'', closing ''newfd'' first if necessary. | |||
If ''newfd'' is omitted, the lowest-numbered unused descriptor will be used for the new descriptor. | |||
====Return Value==== | |||
'''posix.dup()''' returns the new descriptor, or nil, an error string and errno if an error occured. | |||
=errno= | |||
Display the error information | Display the error information | ||
Line 93: | Line 161: | ||
-- a will be nil or 0, b will be No such file or directory or Success | -- a will be nil or 0, b will be No such file or directory or Success | ||
== | =exec= | ||
execute a file | |||
====Synopsis==== | |||
posix.exec(path,[args]) | |||
====Description==== | |||
'''exec'''() replaces the current process image with a new process image. | |||
====Return Value==== | |||
On success '''exec'''() will not return. On error nil, errstr and errno is returned. | |||
=execp= | |||
execute a file using PATH environment variable | |||
====Synopsis==== | |||
posix.execp(path,[args]) | |||
====Description==== | |||
'''execp'''() replaces the current process image with a new process image. If ''path'' does not contain a slash (/) character the file wil be searched for in PATH environment variable. | |||
====Return Value==== | |||
On success '''execp'''() will not return. On error nil, errstr and errno is returned. | |||
=mkfifo= | |||
'''INPUT''' | '''INPUT''' | ||
*PATH- | *PATH- where to make the fifo | ||
'''OUPUT''' | '''OUPUT''' | ||
* | * 0 for success, nil for failure | ||
bar = require "posix" | bar = require "posix" | ||
print(bar.mkfifo("/tmp/bobo")) | |||
--Returns 0 for success, nil for failure | |||
=files= | |||
Returns an interator function that loops over each file in the given directory | |||
'''INPUT''' | '''INPUT''' | ||
*PATH- Directory | *PATH- Directory | ||
'''OUPUT''' | '''OUPUT''' | ||
require "posix" | |||
for name in posix.files("/etc") do | |||
print (name) | |||
end | |||
=fork= | |||
'''INPUT''' | '''INPUT''' | ||
*None | *None | ||
''' | '''OUTPUT''' | ||
returns: -1 on error, 0 to the child process, and the pid of the child to the parent. | |||
require("posix") | |||
for | print ("parent: my pid is: " .. posix.getpid("pid")) | ||
local pid = posix.fork () | |||
if ( pid == -1 ) then | |||
print ("parent: The fork failed.") | |||
elseif ( pid == 0 ) then | |||
print ("child: Hello World! I am pid: " .. posix.getpid("pid") ) | |||
print ("child: I'll sleep for 1 second ... ") | |||
posix.sleep(1) | |||
print ("child: Good bye"); | |||
else | |||
print ("parent: While the child sleeps, I'm still running.") | |||
print ("parent: waiting for child (pid:" .. pid .. ") to die...") | |||
posix.wait(pid) | |||
print ("parent: child died, but I'm still alive.") | |||
print ("parent: Good bye") | |||
end | |||
parent: my pid is: 11050 | |||
child: Hello World! I am pid: 11051 | |||
child: I'll sleep for 1 second ... | |||
parent: While the child sleeps, I'm still running. | |||
parent: waiting for child (pid:11051) to die... | |||
child: Good bye | |||
parent: child died, but I'm still alive. | |||
parent: Good bye | |||
=gmtime= | |||
'''TODO''' | |||
=getcwd= | |||
Get current working directory | |||
'''INPUT''' | '''INPUT''' | ||
*NONE | *NONE | ||
'''OUTPUT''' | '''OUTPUT''' | ||
*String- contents of which is the current working directory | *String- contents of which is the current working directory | ||
require "posix" | |||
print( | print(posix.getcwd()) | ||
=getenv= | |||
'''INPUT''' | '''INPUT''' | ||
*NONE | *NONE | ||
Line 151: | Line 265: | ||
-- Varible - Value | -- Varible - Value | ||
=getgroup= | |||
'''INPUT''' | '''INPUT''' | ||
*GID, or groupname | *GID, or groupname | ||
Line 166: | Line 280: | ||
gid 1 | gid 1 | ||
==getlogin== | =getlogin= | ||
get user name | |||
====Synopsis==== | |||
posix.getlogin() | |||
====Description==== | |||
'''getlogin()''' returns a string containing the name of the user logged in on the controlling terminal of the process, or nil if this information cannot be determined. | |||
====Examples==== | |||
print(posix.getlogin()) | |||
=getrlimit= | |||
'''TODO''' | |||
=getpasswd= | |||
get password file entry | |||
====Synopsis==== | |||
posix.getpasswd(''user'', ''field'') | |||
====Description==== | |||
'''getpasswd()''' queries the local /etc/passwd database. ''user'' can be either an uid or a username. ''field'' is a string of one of '''"uid"''', '''"name"''', '''"gid"''', '''"password"''', '''"gecos"''', '''"dir"''' or '''"shell"'''. | |||
====Return Value==== | |||
Returns the value of ''field'' for ''user''. If ''field'' is omitted, a table with all fields is returned. | |||
====Examples==== | |||
for a,b in pairs(posix.getpasswd("root")) do | |||
print(a,b) | |||
end | |||
Output: | |||
uid 0 | |||
name root | |||
gid 0 | |||
passwd x | |||
gecos root | |||
dir /root | |||
shell /bin/bash | |||
print(posix.getpasswd("root", "shell")) | |||
Output: | |||
/bin/sh | |||
=getprocessid= | |||
'''INPUT''' | '''INPUT''' | ||
*Selector - either [egid,euid,gid,uid,pgrp,pid,ppid,NULL] | *Selector - either [egid,euid,gid,uid,pgrp,pid,ppid,NULL] | ||
Line 204: | Line 343: | ||
Is there a version difference here? AL 1.7.7 calls this "getpid" [[User:Nangel|Nangel]] | Is there a version difference here? AL 1.7.7 calls this "getpid" [[User:Nangel|Nangel]] | ||
==kill | =gettimeofday= | ||
'''TODO''' | |||
=glob= | |||
find pathnames matching a pattern | |||
====Synopsis==== | |||
posix.glob(''pattern'') | |||
====Description==== | |||
The '''glob'''() function searches for all the pathnames matching ''pattern'' according to the rules used by the shell. | |||
====Return Value==== | |||
On successful comlpetion, '''glob'''() returns a table with the filenames. On error '''glob'''() returns nil, errstr and errno. | |||
====Examples==== | |||
for i,j in pairs(posix.glob("/proc/[0-9]*/exe")) do | |||
local f = posix.readlink(j) | |||
if f then | |||
print(f) | |||
end | |||
end | |||
=kill= | |||
'''INPUT''' | '''INPUT''' | ||
*PID- process identifier | *PID- process identifier | ||
Line 216: | Line 377: | ||
---Signals looks to be the number signals accepted in Unix | ---Signals looks to be the number signals accepted in Unix | ||
==link== | =link= | ||
make a new name for a file | |||
====Synopsis==== | |||
posix.dup(''oldpath'', ''newpath''[, ''symbolic'']) | |||
====Description==== | |||
Creates a new name to an existing file. If ''symbolic'' is true the new name will be a symbolic link (soft link), otherwise it will be a hard link. | |||
====Return Value==== | |||
On success, zero is returned. On error '''link'''() returns nil, errstr and errno. | |||
====Examples==== | |||
require "posix" | |||
source="/etc/passwd" | |||
dest="testfile" | |||
status, errstr = posix.link(source, dest, true) | |||
if status == nil then | |||
io.stderr:write(dest..": "..errstr.."\n") | |||
end | |||
=localtime= | |||
'''TODO''' | |||
=mkdir= | |||
create a directory | |||
====Synopsis==== | |||
posix.dup(''pathname'') | |||
====Descritption==== | |||
'''mkdir'''() attempts to create a directory named pathname. | |||
====Return Value==== | |||
'''glob'''() returns 0 on success, or nil, errstr and errno on error. | |||
====Example==== | |||
require "posix" | |||
newdir = "/home/user/bobo" | |||
status, errstr = posix.mkdir(newdir) | |||
if status == nil then | |||
io.stderr:write(newdir..": "..errstr.."\n") | |||
end | |||
=pathconf= | |||
get configuration values for files | |||
====Synopsis==== | |||
posix.pathconf(''path'', ''name'') | |||
====Description==== | |||
'''posix.pathconf()''' gets a value for configuration option ''name'' for the filename ''path''. Setting ''name'' equal to one of the following strings returns the following configuration options: | |||
* '''link_max''' | |||
** returns the maximum number of links to the file. If ''path'' refer to a directory, then the value applies to the whole directory. | |||
* '''max_canon''' | |||
** returns the maximum length of a formatted input line, where ''path'' must refer to a terminal. | |||
* '''max_input''' | |||
** returns the maximum length of an input line, where ''path'' must refer to a terminal. | |||
* '''name_max''' | |||
** returns the maximum length of a filename in the directory ''path'' the process is allowed to create. | |||
* '''path_max''' | |||
** returns the maximum length of a relative pathname when ''path'' is the current working directory. | |||
* '''pipe_buf''' | |||
** returns the size of the pipe buffer, where ''path'' must refer to a FIFO. | |||
* '''chown_restricted''' | |||
** returns non-zero if the chown(2) call may not be used on this file. If ''path '' refer to a directory, then this applies to all files in that directory. | |||
* '''no_trunc''' | |||
** returns non-zero if accessing filenames longer than '''name_max''' generates an error. | |||
* '''vdisable''' | |||
** returns non-zero if special character processing can be disabled, where ''path'' must refer to a terminal. | |||
====Return Value==== | |||
The limit is returned, if one exists. If ''name'' is omitted, a table of all limits is returned. | |||
====Examples==== | |||
for i,j in pairs(posix.pathconf("/dev/tty" )) do | |||
print(i, j) | |||
end | |||
Will ouput: | |||
pipe_buf 4096 | |||
link_max 127 | |||
path_max 4096 | |||
max_canon 255 | |||
chown_restricted 1 | |||
no_trunc 1 | |||
max_input 255 | |||
name_max 255 | |||
vdisable 0 | |||
====References==== | |||
https://man7.org/linux/man-pages/man3/pathconf.3.html | |||
=pipe= | |||
'''TODO''' | |||
====Example==== | |||
require "posix" | |||
rd, wr = posix.pipe() | |||
wr:write("hello, world\n") | |||
wr:close() | |||
print(rd:read("*all")) | |||
rd:close() | |||
=putenv= | |||
'''INPUT''' | '''INPUT''' | ||
* | *STRING- | ||
* | '''OUPUT''' | ||
''' | * 0 if success, nil if not | ||
require "posix" | |||
posix.putenv("DISPLAY=localhost:0") | |||
=readlink= | |||
'''INPUT''' | |||
*PATH-path to link | |||
'''OUPUT''' | |||
* 0 if success, nil if failure | |||
require "posix" | |||
posix.readlink("/etc/rc.d/postfix") | |||
--0 if sucess, nil if failed | |||
=rmdir= | |||
'''INPUT''' | |||
-- 0 for | *PATH- path to directory | ||
'''OUPUT''' | |||
* 0 for sucess | |||
* nil for failure | |||
require "posix" | |||
posix.rmdir("/home/testdir") | |||
-- 0 for success, nil for failure | |||
=setgid= | |||
'''INPUT''' | |||
*Group | |||
** Name or GID | |||
'''OUPUT''' | |||
* 0 for sucess | |||
* nil for failure | |||
require "posix" | |||
posix.setgid("1000") | |||
=setlogmask= | |||
'''TODO''' | |||
=setrlimit= | |||
'''TODO''' | |||
=setuid= | |||
'''INPUT''' | |||
*User | |||
** Name or UID | |||
'''OUPUT''' | |||
*0 for sucess, nil for failure | |||
require "posix" | |||
posix.setuid("1000") | |||
-- 0 for sucess, nil for failure | |||
=sleep= | |||
'''INPUT''' | |||
*SECONDS | |||
'''OUPUT''' | |||
*0 for sucess, nil for failure | |||
require "posix" | |||
posix.sleep(5) | |||
-- will sleep for 5 seconds, usually will not fail | |||
=stat= | |||
'''INPUT''' | |||
*PATH - location of file or direcory | |||
*Selector - | |||
**dev | |||
**type | |||
**ctime | |||
**nlink | |||
**atime | |||
**uid | |||
**mtime | |||
**gid | |||
**mode | |||
**ino | |||
**size | |||
'''OUPUT''' | |||
*If no mode will output as a table with each of the above set | |||
*If mode is set then will give a string with value | |||
require "posix" | |||
bar = posix.stat("/etc/") | |||
for a,b in pairs(bar) do print(a,b) end | |||
dev 769 | |||
type directory | |||
ctime 1194624026 | |||
nlink 113 | |||
atime 1194866712 | |||
uid 0 | |||
mtime 1194624026 | |||
gid 0 | |||
mode rwxr-xr-x | |||
ino 4 | |||
size 6208 | |||
= | =sysconf= | ||
'''INPUT''' | '''INPUT''' | ||
* | *Accept a selector if given anything | ||
''' | **tzname_max | ||
**clk_tck | |||
* | **stream_max | ||
**ngroups_max | |||
**child_max | |||
**open_max | |||
**saved_ids | |||
**job_control | |||
**version | |||
**arg_max | |||
'''OUPUT''' | |||
*TABLE - if no selector | |||
*STRING - if 1 selector | |||
require "posix" | |||
bar = posix.stat() | |||
for a,b in pairs(bar) do print(a,b) end | |||
tzname_max 6 | |||
clk_tck 100 | |||
stream_max 16 | |||
ngroups_max 65536 | |||
child_max 999 | |||
open_max 1024 | |||
saved_ids 1 | |||
job_control 1 | |||
version 200112 | |||
arg_max 131072 | |||
=strftime= | |||
'''TODO''' | |||
=time= | |||
'''TODO''' | |||
=times= | |||
bar. | '''INPUT''' | ||
-- | * | ||
**utime | |||
**cstime | |||
**elapsed | |||
**cutime | |||
**stime | |||
'''OUPUT''' | |||
*TABLE - if non specified output all values in a table | |||
*STING - if one of the above is specified string output | |||
require "posix" | |||
bar = posix.times() | |||
for a,b in pairs(bar) do print(a,b) end | |||
--Maybe takes function calls to see how long they run | |||
= | =ttyname= | ||
'''INPUT''' | '''INPUT''' | ||
* | *NONE | ||
'''OUPUT''' | |||
*STRING - what tty am I on | |||
require "posix" | |||
print(posix.ttyname()) | |||
== | =umask= | ||
'''INPUT''' | |||
*NONE | |||
** or mode, what to change the umask to | |||
'''OUPUT''' | |||
*STRING - what is the current umask set to | |||
** or mode, what to change is to | |||
= | require "posix" | ||
print(posix.umask) | |||
-- rwxr-xr-x | |||
--or change it | |||
posix.umask("a=rwx") | |||
print(posix.umask()) | |||
-- rwxrwxrwx | |||
== | = uname = | ||
get name and information about current kernel | |||
== | ====Synopsis==== | ||
posix.access(''[format]'') | |||
== | ====Description==== | ||
'''uname()''' returns the string ''format'' with directives prefixed by '%' replaced with specified systrem information. If ''format'' is not specified or is nil, then the string "%s %n %r %v %m" will be used. | |||
The format string directives are: | |||
%s - kernel name | |||
%n - network node hostname | |||
%r - kernel release | |||
%v - kernel version | |||
%m - machine hardware name | |||
== | ====Return Value==== | ||
A string with the formatted system information. | |||
== | ====Examples==== | ||
print("Kernel version is: "..posix.uname("%v")) | |||
== | ====References==== | ||
https://man7.org/linux/man-pages/man2/uname.2.html | |||
=utime= | |||
'''INPUT''' | |||
*Path-location of file or directory | |||
**atime - access time | |||
**mtime - modification time | |||
'''OUPUT''' | |||
* 0 for sucess | |||
* nil for failure | |||
require "posix" | |||
posix.utime("/var/log/test",atime,mtime) | |||
=wait= | |||
'''INPUT''' | |||
*PID - process id | |||
'''OUPUT''' | |||
* 0 for success | |||
* nil for failure | |||
require "posix" | |||
posix.wait(10) | |||
---- | ---- | ||
'''If you are using this under linux also get ''' | '''If you are using this under linux also get ''' | ||
==setenv== | =setenv= | ||
'''INPUT''' | |||
*Name- Name of Varible | |||
*Value- What the Name varible should be set to | |||
**overwrite- is this overwriting one already set | |||
'''OUPUT''' | |||
* 0 for sucess, nil for failure | |||
require "posix" | |||
posix.setenv("BAR","YES") | |||
=unsetenv= | |||
'''INPUT''' | |||
*NAME - name of the varible to unset | |||
'''OUPUT''' | |||
* 0 for sucess, nil for failure | |||
require "posix" | |||
posix.unsetenv("BAR") | |||
[[Category:Lua]] | |||
[[Category:ACF]] |
Latest revision as of 20:09, 30 August 2023
This is a list of the Lua Posix functions. Included is helpful snippets of code. Install lua posix. To get this list do:
require "posix" for a in pairs(posix) do print(a) end
access
check real user's permissions for a file
Synopsis
posix.access(pathname, mode)
Description
access() checks whether the calling process can access the file pathname. If pathname is a symbolic link, it is dereferenced.
The mode specifies the accessibility check(s) to be performed, and is either the string "f", or one or more of "r", "w", and "x". "f" tests for the existence of the file. "r", "w", and "x" test whether the file exists and grants read, write, and execute permissions, respectively.
Return Value
On success (all requested permissions granted), zero is returned. On error (at least one char in mode asked for a permission that is denied, or some other error occurred), nil, errorstr and errno is returned.
Examples
status, errstr, errno = posix.access("/etc/passwd", "rw")
if not posix.access("/foo", "f") then print("/foo does not exist") end
References
https://man7.org/linux/man-pages/man2/access.2.html
chdir
change working directory
Synopsis
posix.chdir(path)
Return Value
On success, zero is returned. On error, nil, an error string and errno is returned.
Examples
status, errstr, errno = posix.chdir("/tmp")
if posix.chdir("/tmp") then print("Changed current working dir to:", posix.getpwd()) fi
chmod
change permissions of a file
Synopsis
posix.chmod(path, mode)
Description
The mode of the file given by path is changed.
Modes are specified in one of the following formats
- "rwxrwxrwx" (i.e "rw-rw-w--")
- "ugoa+-=rwx" (i.e "u+w")
- "+-=rwx" (i.e "+w")
Return Value
On success, zero is returned. On error, nil, errstr and errno is returned.
Examples
posix.chmod("/tmp", "a+rwx")
status, errstr = posix.chmod(file, "-w") if not status then print(errstr) fi
chown
INPUT
- Path-location of file or directory
- UID - User id number
- GID - Group id number
OUPUT
- String - 0 is success and nil for failure
bar = require "posix" print(bar.chown("/etc/passwd",100,200) --above will give back nil. Since we printed it will also give back the system errors.
clock_getres
TODO
clock_gettime
TODO
crypt
password and data encryption
Synopsis
posix.crypt(string, salt)
Return Value
On success, zero is returned. On error, nil, an error string and errno is returned.
ctermid
INPUT
- NONE- DISPLAYS the terminal id
OUTPUT
- String with the terminal id
bar = require "posix" print(bar.ctermid())
dir
read a directory
Synopsis
posix.dir(path)
Description
Reads directory path, and returns a table with all the files. If path is omitted, current working dir is read.
Return Value
posix.dir() returns a table with all filenames on succes. On error, nil, an error string and errno is returned.
Examples
files, errstr, errno = posix.dir("/var/log") if files then for a,b in ipairs(files) do print(b) end else print(errstr) end
dup
duplicate a file descriptor
Synopsis
posix.dup(oldfd[, newfd])
Description
posix.dup() creates a copy of the file descriptor oldfd.
newfd will be the copy of oldfd, closing newfd first if necessary.
If newfd is omitted, the lowest-numbered unused descriptor will be used for the new descriptor.
Return Value
posix.dup() returns the new descriptor, or nil, an error string and errno if an error occured.
errno
Display the error information
INPUT
- NONE
OUPUT
- Success, or Error message
bar = require "posix" a,b = bar.dir("/var/foo"), bar.errno() print(a,b) -- a will be nil or 0, b will be No such file or directory or Success
exec
execute a file
Synopsis
posix.exec(path,[args])
Description
exec() replaces the current process image with a new process image.
Return Value
On success exec() will not return. On error nil, errstr and errno is returned.
execp
execute a file using PATH environment variable
Synopsis
posix.execp(path,[args])
Description
execp() replaces the current process image with a new process image. If path does not contain a slash (/) character the file wil be searched for in PATH environment variable.
Return Value
On success execp() will not return. On error nil, errstr and errno is returned.
mkfifo
INPUT
- PATH- where to make the fifo
OUPUT
- 0 for success, nil for failure
bar = require "posix" print(bar.mkfifo("/tmp/bobo")) --Returns 0 for success, nil for failure
files
Returns an interator function that loops over each file in the given directory
INPUT
- PATH- Directory
OUPUT
require "posix"
for name in posix.files("/etc") do print (name) end
fork
INPUT
- None
OUTPUT returns: -1 on error, 0 to the child process, and the pid of the child to the parent.
require("posix") print ("parent: my pid is: " .. posix.getpid("pid")) local pid = posix.fork () if ( pid == -1 ) then print ("parent: The fork failed.") elseif ( pid == 0 ) then print ("child: Hello World! I am pid: " .. posix.getpid("pid") ) print ("child: I'll sleep for 1 second ... ") posix.sleep(1) print ("child: Good bye"); else print ("parent: While the child sleeps, I'm still running.") print ("parent: waiting for child (pid:" .. pid .. ") to die...") posix.wait(pid) print ("parent: child died, but I'm still alive.") print ("parent: Good bye") end
parent: my pid is: 11050 child: Hello World! I am pid: 11051 child: I'll sleep for 1 second ... parent: While the child sleeps, I'm still running. parent: waiting for child (pid:11051) to die... child: Good bye parent: child died, but I'm still alive. parent: Good bye
gmtime
TODO
getcwd
Get current working directory INPUT
- NONE
OUTPUT
- String- contents of which is the current working directory
require "posix" print(posix.getcwd())
getenv
INPUT
- NONE
OUPUT
- Table - Current Environment settings
bar = require "posix" bobo = bar.getenv() for a,b in pairs(bobo) do print(b) end -- Varible - Value
getgroup
INPUT
- GID, or groupname
OUPUT
- TABLE -contents of which hold the group name,gid, and users
bar = require "posix" bobo = bar.getgroup(1000) for a,b in pairs(bobo) do print(a,b) end --if you use pairs then bobo will print also the name and gid or the group --if you use ipairs then just the group members 1 user1 2 user2 name wheel gid 1
getlogin
get user name
Synopsis
posix.getlogin()
Description
getlogin() returns a string containing the name of the user logged in on the controlling terminal of the process, or nil if this information cannot be determined.
Examples
print(posix.getlogin())
getrlimit
TODO
getpasswd
get password file entry
Synopsis
posix.getpasswd(user, field)
Description
getpasswd() queries the local /etc/passwd database. user can be either an uid or a username. field is a string of one of "uid", "name", "gid", "password", "gecos", "dir" or "shell".
Return Value
Returns the value of field for user. If field is omitted, a table with all fields is returned.
Examples
for a,b in pairs(posix.getpasswd("root")) do print(a,b) end
Output:
uid 0 name root gid 0 passwd x gecos root dir /root shell /bin/bash
print(posix.getpasswd("root", "shell"))
Output:
/bin/sh
getprocessid
INPUT
- Selector - either [egid,euid,gid,uid,pgrp,pid,ppid,NULL]
OUPUT
- Number that matches the current process and the selector
bar = require "posix" print(bar.getprocessid("gid")) 18456 --it just printed the current process id for the script or interactive lua.
Is there a version difference here? AL 1.7.7 calls this "getpid" Nangel
gettimeofday
TODO
glob
find pathnames matching a pattern
Synopsis
posix.glob(pattern)
Description
The glob() function searches for all the pathnames matching pattern according to the rules used by the shell.
Return Value
On successful comlpetion, glob() returns a table with the filenames. On error glob() returns nil, errstr and errno.
Examples
for i,j in pairs(posix.glob("/proc/[0-9]*/exe")) do local f = posix.readlink(j) if f then print(f) end end
kill
INPUT
- PID- process identifier
- Signal- to send to the process
OUPUT
bar = require "posix" --kill your current process bobo = bar.getprocessid("pid") bar.kill(bobo,9) ---Signals looks to be the number signals accepted in Unix
link
make a new name for a file
Synopsis
posix.dup(oldpath, newpath[, symbolic])
Description
Creates a new name to an existing file. If symbolic is true the new name will be a symbolic link (soft link), otherwise it will be a hard link.
Return Value
On success, zero is returned. On error link() returns nil, errstr and errno.
Examples
require "posix" source="/etc/passwd" dest="testfile" status, errstr = posix.link(source, dest, true) if status == nil then io.stderr:write(dest..": "..errstr.."\n") end
localtime
TODO
mkdir
create a directory
Synopsis
posix.dup(pathname)
Descritption
mkdir() attempts to create a directory named pathname.
Return Value
glob() returns 0 on success, or nil, errstr and errno on error.
Example
require "posix" newdir = "/home/user/bobo" status, errstr = posix.mkdir(newdir) if status == nil then io.stderr:write(newdir..": "..errstr.."\n") end
pathconf
get configuration values for files
Synopsis
posix.pathconf(path, name)
Description
posix.pathconf() gets a value for configuration option name for the filename path. Setting name equal to one of the following strings returns the following configuration options:
- link_max
- returns the maximum number of links to the file. If path refer to a directory, then the value applies to the whole directory.
- max_canon
- returns the maximum length of a formatted input line, where path must refer to a terminal.
- max_input
- returns the maximum length of an input line, where path must refer to a terminal.
- name_max
- returns the maximum length of a filename in the directory path the process is allowed to create.
- path_max
- returns the maximum length of a relative pathname when path is the current working directory.
- pipe_buf
- returns the size of the pipe buffer, where path must refer to a FIFO.
- chown_restricted
- returns non-zero if the chown(2) call may not be used on this file. If path refer to a directory, then this applies to all files in that directory.
- no_trunc
- returns non-zero if accessing filenames longer than name_max generates an error.
- vdisable
- returns non-zero if special character processing can be disabled, where path must refer to a terminal.
Return Value
The limit is returned, if one exists. If name is omitted, a table of all limits is returned.
Examples
for i,j in pairs(posix.pathconf("/dev/tty" )) do print(i, j) end
Will ouput:
pipe_buf 4096 link_max 127 path_max 4096 max_canon 255 chown_restricted 1 no_trunc 1 max_input 255 name_max 255 vdisable 0
References
https://man7.org/linux/man-pages/man3/pathconf.3.html
pipe
TODO
Example
require "posix" rd, wr = posix.pipe() wr:write("hello, world\n") wr:close() print(rd:read("*all")) rd:close()
putenv
INPUT
- STRING-
OUPUT
- 0 if success, nil if not
require "posix" posix.putenv("DISPLAY=localhost:0")
readlink
INPUT
- PATH-path to link
OUPUT
- 0 if success, nil if failure
require "posix" posix.readlink("/etc/rc.d/postfix") --0 if sucess, nil if failed
rmdir
INPUT
- PATH- path to directory
OUPUT
- 0 for sucess
- nil for failure
require "posix" posix.rmdir("/home/testdir") -- 0 for success, nil for failure
setgid
INPUT
- Group
- Name or GID
OUPUT
- 0 for sucess
- nil for failure
require "posix" posix.setgid("1000")
setlogmask
TODO
setrlimit
TODO
setuid
INPUT
- User
- Name or UID
OUPUT
- 0 for sucess, nil for failure
require "posix" posix.setuid("1000") -- 0 for sucess, nil for failure
sleep
INPUT
- SECONDS
OUPUT
- 0 for sucess, nil for failure
require "posix" posix.sleep(5) -- will sleep for 5 seconds, usually will not fail
stat
INPUT
- PATH - location of file or direcory
- Selector -
- dev
- type
- ctime
- nlink
- atime
- uid
- mtime
- gid
- mode
- ino
- size
OUPUT
- If no mode will output as a table with each of the above set
- If mode is set then will give a string with value
require "posix" bar = posix.stat("/etc/") for a,b in pairs(bar) do print(a,b) end dev 769 type directory ctime 1194624026 nlink 113 atime 1194866712 uid 0 mtime 1194624026 gid 0 mode rwxr-xr-x ino 4 size 6208
sysconf
INPUT
- Accept a selector if given anything
- tzname_max
- clk_tck
- stream_max
- ngroups_max
- child_max
- open_max
- saved_ids
- job_control
- version
- arg_max
OUPUT
- TABLE - if no selector
- STRING - if 1 selector
require "posix" bar = posix.stat() for a,b in pairs(bar) do print(a,b) end tzname_max 6 clk_tck 100 stream_max 16 ngroups_max 65536 child_max 999 open_max 1024 saved_ids 1 job_control 1 version 200112 arg_max 131072
strftime
TODO
time
TODO
times
INPUT
-
- utime
- cstime
- elapsed
- cutime
- stime
OUPUT
- TABLE - if non specified output all values in a table
- STING - if one of the above is specified string output
require "posix" bar = posix.times() for a,b in pairs(bar) do print(a,b) end --Maybe takes function calls to see how long they run
ttyname
INPUT
- NONE
OUPUT
- STRING - what tty am I on
require "posix" print(posix.ttyname())
umask
INPUT
- NONE
- or mode, what to change the umask to
OUPUT
- STRING - what is the current umask set to
- or mode, what to change is to
require "posix" print(posix.umask) -- rwxr-xr-x --or change it posix.umask("a=rwx") print(posix.umask()) -- rwxrwxrwx
uname
get name and information about current kernel
Synopsis
posix.access([format])
Description
uname() returns the string format with directives prefixed by '%' replaced with specified systrem information. If format is not specified or is nil, then the string "%s %n %r %v %m" will be used.
The format string directives are:
%s - kernel name %n - network node hostname %r - kernel release %v - kernel version %m - machine hardware name
Return Value
A string with the formatted system information.
Examples
print("Kernel version is: "..posix.uname("%v"))
References
https://man7.org/linux/man-pages/man2/uname.2.html
utime
INPUT
- Path-location of file or directory
- atime - access time
- mtime - modification time
OUPUT
- 0 for sucess
- nil for failure
require "posix" posix.utime("/var/log/test",atime,mtime)
wait
INPUT
- PID - process id
OUPUT
- 0 for success
- nil for failure
require "posix" posix.wait(10)
If you are using this under linux also get
setenv
INPUT
- Name- Name of Varible
- Value- What the Name varible should be set to
- overwrite- is this overwriting one already set
OUPUT
- 0 for sucess, nil for failure
require "posix" posix.setenv("BAR","YES")
unsetenv
INPUT
- NAME - name of the varible to unset
OUPUT
- 0 for sucess, nil for failure
require "posix" posix.unsetenv("BAR")