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167
votes
10answers
19k views

In Bash, when to alias, when to script, and when to write a function?

It's taken me almost 10 years of Linux usage to ask this question. It was all trial and error and random late-night internet surfing. But people shouldn't need 10 years for this. If I were just ...
18
votes
1answer
2k views

Aliases vs functions vs scripts

This site says, "Shell functions are faster [than aliases]. Aliases are looked up after functions and thus resolving is slower. While aliases are easier to understand, shell functions are preferred ...
11
votes
4answers
5k views

Executing user defined function in a find -exec call

I'm on Solaris 10 and I have tested the following with ksh (88), bash (3.00) and zsh (4.2.1). The following code doesn't yield any result: function foo { echo "Hello World" } find somedir -exec ...
13
votes
5answers
596 views

Stateful bash function

I’d like to implement a function in Bash which increases (and returns) a count with every call. Unfortunately this seems non-trivial since I’m invoking the function inside a subshell and it ...
8
votes
3answers
534 views

Running an executable in PATH with the same name as an existing function

Sometimes I define a function that shadows an executable and tweaks its arguments or output. So the function has the same name as the executable, and I need a way how to run the executable from the ...
24
votes
4answers
2k views

difference between “function foo() {}” and “foo() {}”

I can define bash functions using or omitting the function keyword. Is there any difference? #!/bin/bash function foo() { echo "foo" } bar() { echo "bar" } foo bar Both calls to functions ...
10
votes
2answers
814 views

How to document my custom bash functions and aliases?

Problem: I have multiple bash functions and aliases. I can't remember all of them off the top of my head, so I usually end up opening my .bash_functions and .bash_aliases files to find what I need. ...
6
votes
3answers
6k views

How to add a function to .bash_profile/.profile/bashrc in shell?

I have a function which converts epoch time to date. Here is the definition date1(){ date -d @$1 } I'd like to be able to write: $ data1 xxxyyy And I want the corresponding date. I understand ...
4
votes
3answers
1k views

Infinitely Nested Directories

Let me start off by saying this is a Mac Terminal I'm using. Not Linux, but I assumed I would get the best answers here as it has to do with Unix and the command line not really anything about Mac ...
1
vote
4answers
2k views

how can i use sudo within a function?

i have written a function which acts in a similar way to tee but also pre-pends a datestamp. everything works fine except when i want to output to a file which is only root writeable (in my case a ...
5
votes
2answers
716 views

How can I create a function in zsh that calls an existing command with the same name?

How can I write a function in zsh that invokes an existing command with the same name as the function itself? For example, I've tried this to illustrate my question: function ls { ls -l $1 $2 $3 ...
1
vote
3answers
314 views

What return/exit values can I use in bash functions/scripts?

I want to know what return values we can use that will not be mistaken by for ex. SIGINT? ex.: $sleep 10 $#hit ctrl+c $echo $? 130 so I know I must not use anything like return 130 or exit 130 so ...