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Append a record to the end of a text file: Difference between revisions
Append a record to the end of a text file (view source)
Revision as of 21:08, 15 October 2020
, 3 years ago→{{header|MATLAB}} / {{header|Octave}}
Line 2,036:
xyz:x:1003:1000:X Yz,Room 1003,(234)555-8913,(234)555-0033,xyz@rosettacode.org:/home/xyz/bin/bash
</pre>
=={{header|Nim}}==
{lang Nim>import posix
import strutils
type
# GECOS representation.
Gecos = tuple[fullname, office, extension, homephone, email: string]
# Record representation.
Record = object
account: string
password: string
uid: int
gid: int
gecos: Gecos
directory: string
shell: string
#---------------------------------------------------------------------------------------------------
proc str(gecos: Gecos): string =
## Explicit representation of a GECOS.
result = "("
for name, field in gecos.fieldPairs:
result.addSep(", ", 1)
result.add(name & ": " & field)
result.add(')')
#---------------------------------------------------------------------------------------------------
proc `$`(gecos: Gecos): string =
## Compact representation of a GECOS.
for field in gecos.fields:
result.addSep(",", 0)
result.add(field)
#---------------------------------------------------------------------------------------------------
proc parseGecos(s: string): Gecos =
## Parse a string and return a Gecos tuple.
let fields = s.split(",")
result = (fields[0], fields[1], fields[2], fields[3], fields[4])
#---------------------------------------------------------------------------------------------------
proc str(rec: Record): string =
## Explicit representation of a record.
for name, field in rec.fieldPairs:
result.add(name & ": ")
when typeof(field) is Gecos:
result.add(str(field))
else:
result.add($field)
result.add('\n')
#---------------------------------------------------------------------------------------------------
proc `$`(rec: Record): string =
# Compact representation fo a record.
for field in rec.fields:
result.addSep(":", 0)
result.add($field)
#---------------------------------------------------------------------------------------------------
proc parseRecord(line: string): Record =
## Parse a string and return a Record object.
let fields = line.split(":")
result.account = fields[0]
result.password = fields[1]
result.uid = fields[2].parseInt()
result.gid = fields[3].parseInt()
result.gecos = parseGecos(fields[4])
result.directory = fields[5]
result.shell = fields[6]
#---------------------------------------------------------------------------------------------------
proc getLock(f: File): bool =
## Try to get an exclusive write lock on file "f". Return false is unsuccessful.
var flock = TFlock(l_type: cshort(F_WRLCK), l_whence: cshort(SEEK_SET), l_start: 0, l_len: 0)
result = f.getFileHandle().fcntl(F_SETLK, flock.addr) >= 0
#———————————————————————————————————————————————————————————————————————————————————————————————————
var pwfile: File
const Filename = "passwd"
const Data = ["jsmith:x:1001:1000:Joe Smith,Room 1007,(234)555-8917,(234)555-0077,jsmith@rosettacode.org:/home/jsmith:/bin/bash",
"jdoe:x:1002:1000:Jane Doe,Room 1004,(234)555-8914,(234)555-0044,jdoe@rosettacode.org:/home/jdoe:/bin/bash"]
# Prepare initial file.
# We don'’t use a lock here as it is only the preparation.
pwfile = open(FileName, fmWrite)
for line in Data:
pwfile.writeLine(line)
pwfile.close()
# Display initial contents.
echo "Raw content of initial password file:"
echo "-------------------------------------"
var records: seq[Record]
for line in lines(FileName):
echo line
records.add(line.parseRecord())
echo ""
echo "Structured content of initial password file:"
echo "--------------------------------------------"
for rec in records:
echo str(rec)
echo ""
# Add a new record at the end of password file.
pwfile = open(Filename, fmAppend)
let newRecord = Record(account: "xyz",
password: "x",
uid: 1003,
gid: 1000,
gecos: ("X Yz", "Room 1003", "(234)555-8913", "(234)555-0033", "xyz@rosettacode.org"),
directory: "/home/xyz",
shell: "/bin/bash")
echo "Appending new record:"
echo "---------------------"
echo str(newRecord)
echo ""
if pwfile.getLock():
pwFile.writeLine(newRecord)
pwfile.close()
else:
echo "File is locked. Quitting."
pwFile.close()
quit(QuitFailure)
# Reopen the file and display its contents.
echo "Raw content of updated password file:"
echo "-------------------------------------"
for line in lines(FileName):
echo line</lang>
{{out}}
<pre>Raw content of initial password file:
-------------------------------------
jsmith:x:1001:1000:Joe Smith,Room 1007,(234)555-8917,(234)555-0077,jsmith@rosettacode.org:/home/jsmith:/bin/bash
jdoe:x:1002:1000:Jane Doe,Room 1004,(234)555-8914,(234)555-0044,jdoe@rosettacode.org:/home/jdoe:/bin/bash
Structured content of initial password file:
--------------------------------------------
account: jsmith
password: x
uid: 1001
gid: 1000
gecos: (fullname: Joe Smith, office: Room 1007, extension: (234)555-8917, homephone: (234)555-0077, email: jsmith@rosettacode.org)
directory: /home/jsmith
shell: /bin/bash
account: jdoe
password: x
uid: 1002
gid: 1000
gecos: (fullname: Jane Doe, office: Room 1004, extension: (234)555-8914, homephone: (234)555-0044, email: jdoe@rosettacode.org)
directory: /home/jdoe
shell: /bin/bash
Appending new record:
---------------------
account: xyz
password: x
uid: 1003
gid: 1000
gecos: (fullname: X Yz, office: Room 1003, extension: (234)555-8913, homephone: (234)555-0033, email: xyz@rosettacode.org)
directory: /home/xyz
shell: /bin/bash
Raw content of updated password file:
-------------------------------------
jsmith:x:1001:1000:Joe Smith,Room 1007,(234)555-8917,(234)555-0077,jsmith@rosettacode.org:/home/jsmith:/bin/bash
jdoe:x:1002:1000:Jane Doe,Room 1004,(234)555-8914,(234)555-0044,jdoe@rosettacode.org:/home/jdoe:/bin/bash
xyz:x:1003:1000:X Yz,Room 1003,(234)555-8913,(234)555-0033,xyz@rosettacode.org:/home/xyz:/bin/bash</pre>
=={{header|Perl}}==
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