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1
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1answer
28 views

find with -exec eval of $0 [duplicate]

In the following command I would like to know why $0 was evaluated to the file found by find and not the echo command. $ find . -type f -perm -u=x -exec bash -c ' /bin/echo $0 is the name of the ...
0
votes
0answers
54 views

Gummiboot Kernel Parameters, Cannot find /boot/loader dir

I installed Gummi boot to my EUEFI partition which is sda1. when I do lsblk it show boot is mounted on sda2, which is also my root partition. when I ls '/boot' there is no loader dir. I need the ...
0
votes
0answers
20 views

Automated function Logging tool

Is there a automated tool for logging function name , function entry and exit parameters per thread for complex multi threaded application.(C / C++)
0
votes
3answers
51 views

Bash: Access parameter passed to last command [duplicate]

This is a situation I often find myself in: mkdir /Some/really/long/path/to/a/directory/ cd /Some/really/long/path/to/a/directory/ I know that ideally you would cd /Some/...etc.../a/ and then mkdir ...
0
votes
0answers
43 views

isolcpus doesn't work on Ubuntu 14

I added isolcpus=0 to the end of the following line to the file /etc/default/grub GRUB_CMDLINE_LINUX_DEFAULT="quiet splash isolcpus=0" The idea, as I understand it, is to reserve core 0 from having ...
0
votes
2answers
54 views

What is the variable of $#?

I'm learning introductory Linux and came across something which I did not understand: "The following command has been executed: set 10 20 30 40 50 Enter the value of the variable $#: I understand ...
2
votes
2answers
138 views

An error of variable type?

I've an error that I don't understand, it seems that that the problem is that my parameters into the shell are not of the same type as what they are in my SQL Database. For a better understanding: ...
3
votes
3answers
11k views

How do I echo just 1 column of output from ls command?

Lets say when I do ls command the output is: file1 file2 file3 file4 Is it possible to display only a certain column of output, in this case file2? I have tried the following with no success: echo ...
1
vote
2answers
278 views

How to put $@ in quotes?

My bash script looks like this: #!/bin/bash grep -r --color=always $@ . | nolong The file is saved in /usr/bin/findstr Everything's ok when I run this: findstr hello But when I run this: ...
0
votes
0answers
19 views

Add extra parameter for text label or just echo it outside the call?

I have written a program that allows me to test my functions. I call it like this: do_test function_name expected_result parm1 parm2 For example do_test add_2_nums 10 5 5 Now I need to call the ...
2
votes
1answer
114 views

Bash - Split quoted parameters

I have a script which gets called with two parameters: ./script.sh a b I'm currently reading them through $1 and $2 (such as cd $1). My problem is that the output needs to be the same for when the ...
4
votes
3answers
1k views

How to tell of whether the kernel parameter [passed at command line] is a valid kernel parameter?

In the grub.conf configuration file I can specify command line parameters that the kernel will use, i.e.: kernel /boot/kernel-3-2-1-gentoo root=/dev/sda1 vga=791 plasticDuck After booting up a ...
0
votes
2answers
1k views

Convert input string to date in shell script

My shell script: #!/bin/bash echo "$1"; startd=$(date -d "$1" +"%Y%m%d"); echo "$startd"; My command: sudo ./test.sh "20151010" The output: 20151010 20150213 it printed todays date ...
2
votes
3answers
281 views

How can I pass on parameters 4..99 to another function

I'm calling a function and I want to pass up to 100 paramters onto another function. I do not want to pass on the first 3 params, I start with param4 being the first param for the other program. I ...
1
vote
3answers
179 views

How to pass an array to a function as an actual parameter rather than a global variable

Is there a way to pass an array to a function as one of its parameters? Currently I have #!/bin/bash highest_3 () { number_under_test=(${array[@]}) max_of_3=0 for ((i = 0; ...
8
votes
2answers
435 views

Is it possible to use shell parameter variables ($1, …, $@) directly in CLI?

Sometimes it is necessary to emulate and verify the above variables in small examples and then can be copied immediately to some script, etc. I tried to solve by using a simple example in the ...
1
vote
3answers
48 views

How to access the contents of a file that is used as an argument when running a bash script?

I am running a bash script with its parameters/arguments as files. From inside the script, how do I get the contents of those files? I run the script with this command line: sh script_name ...
2
votes
3answers
171 views

Print file name extension using -exec in find

I am playing around with -exec flag of find command. I am trying to use the flag to print the extension name of files, using a fairly new Linux distribution release. Starting simple, this works: ...
2
votes
3answers
374 views

How to pass the content of a file as multiple arguments in bash

I have a file that contains data that gets updated over time (mydata). The file looks like this: 1 2 3 With this file, I want to do this (basically handle each number as a separate parameter): ...
2
votes
1answer
91 views

how handle a path ($1)

I've: /home/wms/mp3/ and /home/wms/tmp/ Inside ~/tmp my script: #!/bin/bash br=64 for a in "$1"*.mp3 ; do ffmpeg -i "$a" -ar 44100 -ab $br "$br""_tmp/${a%.*} ["$br"].mp3" ; done I do: ...
1
vote
2answers
123 views

Bash script loop to grow parameters

I want to use whiptail to generate a checkbox list based on the output from another program. Only the first word on each line of the output from the first program is necessary, so I extract it using ...
2
votes
2answers
475 views

Want a seperate file to store mysql username, password, and database name

I have as script that dumps a mysql database, and compresses the file. What I want to do is have another (edit) file which can change the username, password and database name. Then somehow connecting ...
14
votes
4answers
2k views

What does echo $-1 display?

What does the output of echo $-1, echo $-2, echo $-3.. mean? On one of my Linux boxes, it shows me: echo $-1 imsBEl1 echo $-2 imsBEl2 And on another Linux box, it shows: echo $-1 himBH1 echo $-2 ...
14
votes
2answers
28k 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?
13
votes
2answers
516 views

When running a shell script, is it possible to pass specific positional parameters without having to enter them all in order?

For example, if I have script ./foo that takes 10 parameters, and I only want to pass the 8th parameter. The only way I know how to do this currently is: ./foo '' '' '' '' '' '' '' 'bar' Is there ...
1
vote
2answers
120 views

Shell syntax question with difficult parameter expansion

I am scratching my head to understand this script and can certainly use some expert advice. getopt_simple() { echo "getopt_simple()" echo "Parameters are '$*'" until [ -z "$1" ] do ...
2
votes
1answer
77 views

Parameter substitution and error messages: suppressing line numbers etc

Here is my example file: !/bin/bash # argument-one # Is first argument missing? # First method [[ "$1" == "" ]] && echo "Usage: $(basename $0) filename"; exit 1 # Second method # ...
0
votes
1answer
68 views

Special Parameter query - multiple used to obtain command name? [duplicate]

In a uni text provided us to cover bash scripting, the following variable assignment has got be stumped and I've yet to get an answer back from anyone, hence hopefully someone on here can help. ...
2
votes
3answers
135 views

Why are POSIX Find Parameters Different from Other Program styles?

Why is a parameter in the POSIX find command added with a single hyphen for multi-character parameter names, while most other programs use single hyphen to indicate multiple single-character flags, ...
3
votes
1answer
61 views

Customize bash to always include a certain parameter

When using the "ls" command, bash prints in the following format: file1 file2 file3 file4 file5 file6 file7 file8 But when given the parameter "-1", it prints: file1 file2 file3 etc... Is there ...
2
votes
2answers
450 views

What is the bash syntax for extracting the values from multiple instances of the same argument?

I want to use multiple instances of command line paramater such as the -d option used by PHP for passing PHP options. I am currently using the getopts command in bash. With PHP invocation it would ...
2
votes
2answers
3k views

GRUB2 and kernel vga= parameter

According to the documentation, use of the vga= kernel parameter is deprecated as of GRUB2. The fact that some newer kernels don't seem to support it anymore on certain adapters is of no concern as ...
1
vote
1answer
881 views

What's the right way to set Linux kernel runtime parameters?

What's the prescribed way to set Linux kernel runtime parameters? I've seen sometimes that people will set these in files such as /etc/rc.local. Is this really the right way to do this?
1
vote
1answer
1k views

Permanently set kernel parameters [isolcpus] without grub?

Is there any way to set kernel parameters in an Ubuntu-based system without relying on grub? (not available in the target environment) Specifically I want to set the isolcpus parameter to dedicate ...
4
votes
1answer
204 views

Use boot parameter to perform certain actions after boot

I'm asking myself if I can use Grub 2 to tell the Operating System which actions to perform after boot. Background: I have a HTPC with Debian Wheezy installed. Sometimes I want to use the System as a ...
0
votes
1answer
155 views

How can I pass in a parameter to sed?

To be more precise - how can I pass in a parameter to a program that then calls sed - how can I 'pass' that parameter along? I have a file 'source_code.sc'. I have a sed script "find_expect": #n ...
2
votes
1answer
112 views

How to manipulate all parameters of a shell script at once?

While for a finite amount of parameters one can explicitly do something like wrapped_function "${1#prefix}" "${2#prefix}" "${3#prefix}" # etc., isn't there a simpler way to manipulate all ...
12
votes
0answers
356 views

Should I use $* or $@? [duplicate]

Which one of $* or $@ is better to use (in array syntax,command line parameters, etc.) to avoid any bugs/problems in code? Or it does not make any difference?
2
votes
1answer
752 views

Execute command supplied by function parameters

I'm trying to create a function method in a bash script that executes a command which is supplied to the method by the paramters. Meaning somethings like this: special_execute() { # Some code ...
2
votes
1answer
157 views

prevent trap from altering underscore variable $_

I have the following code in my bashrc to get the execution time of the last command from http://stackoverflow.com/a/1862762 function timer_start { timer=${timer:-$SECONDS} } function timer_stop { ...
4
votes
2answers
290 views

Why is $# always 0 in my function?

Bash is driving me nuts. I can't figure out why the following (nor any of the dozens of variations I've literally copied and pasted from examples) fails to work: #!/bin/bash echo $# function main { ...
2
votes
1answer
654 views

Bash: slice of positional parameters

How can I get a slice of $@ in Bash without first having to copy all positional parameters to another array like this? argv=($@) echo ${argv[@]:2};
6
votes
3answers
5k 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 ...
2
votes
4answers
1k 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 ...
5
votes
4answers
513 views

How can I create a empty file whose name begins with a dash? [duplicate]

How can we create a empty file with the unix name -stuff. It means the name start with -. I tried with touch -stuff but it didn't work.
3
votes
2answers
460 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. ...
12
votes
2answers
2k 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 ...
3
votes
2answers
165 views

Should stdin or filenames be discarded if both are provided?

grep and sed ignore stdin if you provide a filename parameter: $ echo foo > test.txt $ echo foobar | grep f test.txt foo $ echo foobar | sed -e 's/foo/bar/' test.txt bar Is this established ...
2
votes
2answers
95 views

Parameter expansion seems to be missing a piece

I'm currently learning how to write simple scripts and can't get my head around a very simple problem. I have the following command in my script... touch ${DIRECTORY}/${FILE} This command appears ...
2
votes
2answers
136 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. ...