Tcl

Read the Target of a Symbolic Link

Demonstrates the Chilkat SFtp.ReadLink method, which returns the target path stored in a remote symbolic link. The only argument is the link path. The example then resolves the target to an absolute path with RealPath.

Background: ReadLink returns the raw string stored in the link exactly as it was created — which may be relative, absolute, or even dangling — without resolving it. That distinction matters: to learn where a link actually leads you follow it with RealPath, which canonicalizes the path on the server. Reading the raw target is the right choice when you need to inspect or preserve the link itself rather than its destination.

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Tcl


load ./chilkat.dll

set success 0

#  Demonstrates the SFtp.ReadLink method, which returns the target path stored in a remote
#  symbolic link.  The only argument is the link path.

set sftp [new_CkSFtp]

#  Connect, authenticate, and initialize the SFTP subsystem.
set port 22
set success [CkSFtp_Connect $sftp "sftp.example.com" $port]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  Normally you would not hard-code the password in source.  You should instead obtain it
#  from an interactive prompt, environment variable, or a secrets vault.
set password "mySshPassword"

set success [CkSFtp_AuthenticatePw $sftp "mySshLogin" $password]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

set success [CkSFtp_InitializeSftp $sftp]
if {$success == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

#  Read the target of a symbolic link.  The returned value is the raw target string stored in
#  the link; it is not canonicalized and can be relative or absolute.
set target [CkSFtp_readLink $sftp "subdir/latest.log"]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

puts "The link points to: $target"

#  To resolve it to an absolute path, pass it to RealPath.
set absTarget [CkSFtp_realPath $sftp $target ""]
if {[CkSFtp_get_LastMethodSuccess $sftp] == 0} then {
    puts [CkSFtp_lastErrorText $sftp]
    delete_CkSFtp $sftp
    exit
}

puts "Absolute target: $absTarget"

CkSFtp_Disconnect $sftp

delete_CkSFtp $sftp