Sponsored Content
Full Discussion: What is a function exactly
Top Forums UNIX for Dummies Questions & Answers What is a function exactly Post 302346399 by Straitsfan on Friday 21st of August 2009 07:36:23 PM
Old 08-21-2009
What is a function exactly

I'm reading about function from my book on bash ("learning the bash shell"), But I'm not exactly sure what a function is -- sometimes the definitions are quite dry and or unclear. What is the difference between a function and a shell script?

And by the way, does anyone know of any other books on the bash shell that may not be as dry as the one I'm currently reading?

Follow up -- can someone also tell me what is a built in -- sometimes for example I'll type, say man cd and I'll get a page on all the builtin commands, which says this:

Shell builtin commands are commands that can be executed within the running shell's process.

Exactly what does that mean?
 

10 More Discussions You Might Find Interesting

1. Shell Programming and Scripting

Passing global variable to a function which is called by another function

Hi , I have three funcions f1, f2 and f3 . f1 calls f2 and f2 calls f3 . I have a global variable "period" which i want to pass to f3 . Can i pass the variable directly in the definition of f3 ? Pls help . sars (4 Replies)
Discussion started by: sars
4 Replies

2. Shell Programming and Scripting

Return a value from called function to the calling function

I have two scripts. script1.sh looks -------------------------------- #!/bin/bash display() { echo "Welcome to Unix" } display ----------------------------- Script2.sh #!/bin/bash sh script1.sh //simply calling script1.sh ------------------------------ (1 Reply)
Discussion started by: mvictorvijayan
1 Replies

3. Programming

Function pointer to inline function ?

Hi. Problem: I have to parse the payload of a packet. The payload could be in Big Endian Format (network byte order) or little. That depends on a flag present in the header of the packet. Solution: A horrible solution could be to check for that flag everytime I have to read a field in the... (11 Replies)
Discussion started by: emitrax
11 Replies

4. Shell Programming and Scripting

SHELL SCRIPT Function Calling Another Function Please Help...

This is my function which is creating three variables based on counter & writing these variable to database by calling another function writeRecord but only one record is getting wrote in DB.... Please advise ASAP...:confused: function InsertFtg { FTGSTR="" echo "Saurabh is GREAT $#" let... (2 Replies)
Discussion started by: omkar.sonawane
2 Replies

5. Programming

How to step in one function after the function be executed in gdb?

In gdb, I can call one function with command "call", but how can I step in the function? I don't want to restart the program, but the function had been executed, gdb will execute next statement, and I don't know how to recall the function. (4 Replies)
Discussion started by: 915086731
4 Replies

6. Shell Programming and Scripting

Help to Modify File Name in each function before calling another function.

I have a script which does gunzip, zip and untar. Input to the script is file name and file directory (where file is located) I am reading the input parameters as follows: FILENAME=$1 FILEDIR=$2 I have created 3 functions that are as follows: 1) gunzip file 2) unzip file... (2 Replies)
Discussion started by: pinnacle
2 Replies

7. Shell Programming and Scripting

Passing variable value in a function to be used by another function

Hello All, I would like to ask help from you on how to pass variable value from a function that has been called inside the function. I have created below and put the variables in " ". Is there another way I can do this? Thank you in advance. readtasklist() { while read -r mod ver... (1 Reply)
Discussion started by: aderamos12
1 Replies

8. Shell Programming and Scripting

Will files, creaetd in one function of the same script will be recognized in another function?

Dear All. I have a script, which process files one by one. In the script I have two functions. one sftp files to different server the other from existing file create file with different name. My question is: Will sftp function recognize files names , which are created in another... (1 Reply)
Discussion started by: digioleg54
1 Replies

9. Shell Programming and Scripting

Need help on awk for printing the function name inside each function

Hi, I am having script which contains many functions. Need to print each function name at the starting of the function. Like below, functionname() { echo "functionname" commands.... } I've tried like below, func=`grep "()" scriptname | cut -d "(" -f1` for i in $func do nawk -v... (4 Replies)
Discussion started by: Sumanthsv
4 Replies

10. Shell Programming and Scripting

Function - Make your function return an exit status

Hi All, Good Day, seeking for your assistance on how to not perform my 2nd, 3rd,4th etc.. function if my 1st function is in else condition. #Body function1() { if then echo "exist" else echo "not exist" } #if not exist in function1 my all other function will not proceed.... (4 Replies)
Discussion started by: meister29
4 Replies
LIBBASH(7)							  libbash Manual							LIBBASH(7)

NAME
libbash -- A bash shared libraries package. DESCRIPTION
libbash is a package that enables bash dynamic-like shared libraries. Actually its a tool for managing bash scripts whose functions you may want to load and use in scripts of your own. It contains a 'dynamic loader' for the shared libraries ( ldbash(1)), a configuration tool (ldbashconfig(8)), and some libraries. Using ldbash(1) you are able to load loadable bash libraries, such as getopts(1) and hashstash(1). A bash shared library that can be loaded using ldbash(1) must answer 4 requirments: 1. It must be installed in $LIBBASH_PREFIX/lib/bash (default is /usr/lib/bash). 2. It must contain a line that begins with '#EXPORT='. That line will contain (after the '=') a list of functions that the library exports. I.e. all the function that will be usable after loading that library will be listed in that line. 3. It must contain a line that begins with '#REQUIRE='. That line will contain (after the '=') a list of bash libraries that are required for our library. I.e. every bash library that is in use in our bash library must be listed there. 4. The library must be listed (For more information, see ldbashconfig(8)). Basic guidelines for writing library of your own: 1. Be aware, that your library will be actually sourced. So, basically, it should contain (i.e define) only functions. 2. Try to declare all variables intended for internal use as local. 3. Global variables and functions that are intended for internal use (i.e are not defined in '#EXPORT=') should begin with: __<library_name>_ For example, internal function myfoosort of hashstash library should be named as __hashstash_myfoosort This helps to avoid conflicts in global name space when using libraries that come from different vendors. 4. See html manual for full version of this guide. AUTHORS
Hai Zaar <haizaar@haizaar.com> Gil Ran <ril@ran4.net> SEE ALSO
ldbash(1), ldbashconfig(8), getopts(1), hashstash(1) colors(1) messages(1) urlcoding(1) locks(1) Linux Epoch Linux
All times are GMT -4. The time now is 11:21 AM.
Unix & Linux Forums Content Copyright 1993-2022. All Rights Reserved.
Privacy Policy