Tagged Questions
2
votes
4answers
110 views
How to write a very simple wrapper that provides default parameters?
Given a program that requires some parameters, e.g. program -in file.in -out file.out, what would be the simple-most approach to write a bash script that could be called with or without any of these ...
2
votes
2answers
90 views
$BASHPID And $$ differ in some cases
I'm reading "BASH pocket guide of Oreilly".
It said:
The process ID of the current Bash process.
In some cases, this can differ from $$.
Above explanation , explained $BASHPID variable.
...
2
votes
2answers
105 views
Parameter splitting
I have a bash script that is a simple wrapper around another process:
$ cat ~/bin/s3cmd
#!/bin/sh
trickle -u 80 ~/bin/s3cmd.py $*
$
This works great when the parameters don't contain spaces. ...
3
votes
2answers
167 views
Function caller positional parameters
I need to read and write the positional parameters $@ of a function's caller. The Bash man page says that:
A shell function is an object that is called like a simple command and
executes a ...
1
vote
1answer
118 views
Is it possible to use a parameter within an alias command [duplicate]
Possible Duplicate:
How to pass parameters to an alias?
As answered in Can less retain colored output? I want to use git diff --color=always filename | less -r to get a colored output of my ...
4
votes
2answers
259 views
Passing parsed output of sed to find (in this direction)
Well, I think you can find dozens of questions on this platform how to pipe find output to sed, but I haven't found anything for the reverse direction so far. What I want to do is modify my input, and ...
7
votes
2answers
586 views
What does `:-` mean in a shell script
I saw this in the end of an awesome shell script but I can't understand the login here because I think it's being short-handed for a longer command.
spark ${@:-`cat`}
This apears at the end of this ...
5
votes
3answers
1k views
Transform an array into arguments of a command?
I have an array of "options" of a command.
my_array=(option1 option2 option3)
I want to call this command in a bash script, using the values from array as options. So, command $(some magic here ...
5
votes
1answer
4k views
How to check if there are no parameters provided to a command?
How do you check if $* is empty? In other words, how to check if there were no arguments provided to a command?
10
votes
1answer
377 views
How do ${0##*/} and ${0%/*} work?
I'm quite confused about the following regular expressions I found in a shell script:
${0##*/}
${0%/*}
How do they work?
4
votes
3answers
2k views
Print shell arguments in reverse order
I am a bit stuck. My task is to print the arguments to my script in reverse order except the third and fourth.
What I have is this code:
#!/bin/bash
i=$#
for arg in "$@"
do
case $i
in
...
3
votes
3answers
1k views
How to pass a string parameter on bash function?
I have this code that does work:
get_parameter ()
{
echo "$query" | sed -n 's/^.*name=\([^&]*\).*$/\1/p' | sed "s/%20/ /g"
}
But I want to replace the "name" with the parameter that I pass ...
10
votes
2answers
829 views
How to safely pass variables to root-enabled scripts?
This question is totally general and not only applicable to my situation, but... I have a small busybox appliance where I want a non-root user to be able to execute a particular script with root ...
6
votes
5answers
1k views
Indexing and modifying Bash parameter array $@
Is it possible to refer to indexes in $@? I can't find any reference to use like the following anywhere in GrayCat's wiki, and the Advanced Scripting Guide and others assign this to a different ...
5
votes
3answers
3k views
How do I split the $0 variable to find directory and relative paths in bash?
The $0 variable contains the path info of the script.
How can I change the path info to absolute path? I mean how to process ~, ., .. or similar?
How can I split the path info into directory and ...
