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en:utility-scripts:chttl [2025/01/06 06:12] – [chttl] Webmaster VitaNetworksen:utility-scripts:chttl [2025/01/06 07:46] (current) – Webmaster VitaNetworks
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 ''chttl'' — Temporarily override the system's default TTL. ''chttl'' — Temporarily override the system's default TTL.
- 
-<WRAP center round tip 80%> 
-===== Make it a function ===== 
-This was originally written as a bash function. It was changed early on to ''sh'' for portability reasons but nevertheless it was wrapped in a single unit to make it easy to change it back. Simply remove the first and last lines, then add the remaining code to your bash functions file(s). 
-</WRAP> 
  
 ===== What does it do? ===== ===== What does it do? =====
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 ===== Is there something else? ===== ===== Is there something else? =====
-- This is the first [intentionaly] POSIX-compliant script we've ever written. +- This is the first [intentionaly] POSIX-compliant script we've ever written.\\  
-- It works on macOS, Linux and FreeBSD. +- It works on macOS, Linux and FreeBSD.\\  
-- It can be used to set the value back to where it was as well, simply add it at the end. +- It can be used to set the value back to where it was as well, simply add it at the end.\\  
-- It's not a permanent modification. +- It's not a permanent modification.\\  
-  Depending on the OS, you might need to create a file in a specific location or issue a special command that sets preference files.+  - Depending on the OS, you might need to create a file in a specific location or issue a special command that sets preference files. 
 + 
 +==== Make it a function ==== 
 +This was originally written as a bash function. It was changed early on to ''sh'' for portability reasons but nevertheless it was wrapped in a single unit to make it easy to change it back. All you need is to remove the shebang (first) line and the call out or invocation (last) line from the script. Then paste the remainder of the code in your bash functions file(s). 
 + 
 +=== Using a functions file === 
 +As a login shell, bash process config files in the following order: 
 +- ''/etc/profile'' 
 +- ''~/.bash_profile'' 
 +- ''~/.bash_login'', and 
 +- ''~/.profile'', 
 +Typically ''~/.bash_profile'' would call ''~/.bashrc'' which will be executed every single new CLI session. i.e;\\  
 +''if [ -f ~/.bashrc ]; then . ~/.bashrc; fi''\\  
 +(meaning "//if ''~/.bashrc'' exists, run it// ".) 
 + 
 +You may follow the bash's own example by invoking the functions file from ''~/.bash_profile'' e.g; ''if [ -f "${HOME}/bin/bashfunctions" ]; then . "${HOME}/bin/bashfunctions"; fi'' where the file was created to live alongside your scritps on ''"${HOME}/bin"'' and it would be a much easier job syncing things across systems. 
 +<code> 
 +[Sun05@23:20:52][vuser@vpro:~] $〉ls 
 +total n 
 + 24 -rw-------    1 vuser  vgroup    12K Jan  5 23:04 .bash_history 
 +  8 -rw-r-xr-x@   1 vuser  vgroup   1.7K Oct 25 16:51 .bash_profile* 
 +######################################################################################################## 
 +#↑↑↑ Add 'if [ -f "${HOME}/bin/bashfunctions" ]; then . "${HOME}/bin/bashfunctions"; fi'            ↑↑↑# 
 +######################################################################################################## 
 +  8 -rw-r--r--    1 vuser  vgroup   1.5K Jul  3  2024 .bash_profile.bak 
 +  8 -rw-r-xr-x@   1 vuser  vgroup   1.1K Mar 27  2024 .bash_profile.pysave* 
 +  0 drwx------   16 vuser  vgroup   512B Oct  7 16:09 .bash_sessions/ 
 + 16 -rw-r-xr-x@   1 vuser  vgroup   4.7K Oct 14 16:01 .bashrc* 
 +  0 drwxr-xr-x  172 vuser  vgroup   5.4K Jan  5 16:18 bin/
  
 +[Sun05@23:50:41][vuser@vpro:~] $〉ls bin
 +total n
 +   0 drwxr-xr-x  12 vuser  vgroup   384B Mar 20  2024 .git/
 +   8 -rwxr-xr-x   1 vuser  vgroup    86B May  1  2022 .zshrc*
 +   0 drwxr-xr-x  17 vuser  vgroup   544B Sep 22  2020 argbash/
 +   0 drwxr-xr-x   2 vuser  vgroup    64B Feb  9  2023 assets/
 +   8 -rwxr-xr-x   1 vuser  vgroup   102B May  1  2022 backupbashp*
 +   8 -rwxr-xr-x   1 vuser  vgroup   2.6K Oct 18 13:02 bashaliases*
 +  16 -rwxr-xr-x@  1 vuser  vgroup   6.8K Jan  5 00:10 bashfunctions*
 +########################################################################################################
 +#↑↑↑         Functions file example                                                                 ↑↑↑#
 +########################################################################################################
 +   8 -rwxr-xr-x   1 vuser  vgroup   3.5K Nov  1 17:20 bashvars*
 +   8 -rwxr-xr-x   1 vuser  vgroup    30B May  1  2022 catprivkey*
 +   8 -rwxr-xr-x   1 vuser  vgroup    34B May  1  2022 catpubkey*
 +  40 -rwxr-xr-x   1 vuser  vgroup    20K Feb 25  2023 ciscokvm*
 +   8 -rwxr-xr-x   1 vuser  vgroup   119B Oct  3 02:04 codehere*
 +   8 -rwxr-xr-x   1 vuser  vgroup   235B May  1  2022 fixsmb*
 +   8 -rwxr-xr-x   1 vuser  vgroup    55B May  1  2022 fixsshperms*
 +   8 -rwxr-xr-x@  1 vuser  vgroup   1.0K Jul 11 07:30 flushdns*
 +   8 -rwxr-xr-x   1 vuser  vgroup   128B May 28  2022 getcerts*
 +   8 -rwxr-xr-x   1 vuser  vgroup   262B May 28  2022 getmstr*
 +   8 -rwxr-xr-x   1 vuser  vgroup    51B May  1  2022 hapchk*
 +   8 -rwxr-xr-x   1 vuser  vgroup   243B May  1  2022 hapcmd*
 +   8 -rwxr-xr-x   1 vuser  vgroup    52B May  1  2022 hapinfo*
 +   8 -rwxr-xr-x   1 vuser  vgroup    40B May  1  2022 hapjrnl*
 +  64 -rwxr-xr-x   1 vuser  vgroup    30K Oct 23  2022 hapreset*
 +   8 -rwxr-xr-x   1 vuser  vgroup    51B May  1  2022 hapstart*
 +   8 -rwxr-xr-x   1 vuser  vgroup    50B May  1  2022 hapstop*
 +   8 -rwxr-xr-x@  1 vuser  vgroup   2.6K Nov 11 17:49 heupdate*
 +   8 -rwxr-xr-x   1 vuser  vgroup   1.8K Oct 31 17:59 lopkg*
 +   8 -rwxr-xr-x   1 vuser  vgroup   1.9K Oct 23  2022 lports*
 +   8 -rwxr-xr-x   1 vuser  vgroup   272B May  1  2022 lsvch*
 +  40 -rwxr-xr-x   1 vuser  vgroup    17K Apr 22  2024 pppkg*
 +  48 -rwxr-xr-x   1 vuser  vgroup    21K Jan  1  2023 ppull*
 +  32 -rwxr-xr-x@  1 vuser  vgroup    15K Apr  9  2024 ppush*
 +  24 -rwxr-xr-x   1 vuser  vgroup    11K Nov  3  2022 printMESSAGE*
 +   8 -rwxr-xr-x   1 vuser  vgroup    80B May  1  2022 rmkh*
 +  16 -rwxr-xr-x   1 vuser  vgroup   5.6K Jan 21  2023 rmkhk*
 +   8 -rwxr-xr-x   1 vuser  vgroup    41B Dec  7  2022 vimhosts*
 +   8 -rwxr-xr-x   1 vuser  vgroup    30B May  1  2022 vimsshconfig*
 +  40 -rwxr-xr-x@  1 vuser  vgroup    19K Nov 18 09:42 vncadeploy*
 + 176 -rwxr-xr-x   1 vuser  vgroup    84K Jan 23  2023 vprep*
 +   8 -rwxr-xr-x   1 vuser  vgroup   3.8K Oct 20  2023 vsphere2unraid*
 +   8 -rwxr-xr-x   1 vuser  vgroup   505B Jan 22  2024 xdex*
 +   8 -rwxr-xr-x   1 vuser  vgroup   403B Dec 17  2022 zfsarctune*
 +</code> 
 ===== Syntax ===== ===== Syntax =====
 The script takes one or no arguments; any additional argument(s) after the first one should be ignored. The script takes one or no arguments; any additional argument(s) after the first one should be ignored.