small programs used on the command line to do a specific job

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4
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1answer
2k views

Where does the “export” command come from?

Why doesn't the whereis command give any information about the export command? How does the export command work even if the shell path variable is set to null?
12
votes
2answers
2k views

Is '-9' a flag to kill command?

What does -9 do? It does not show up in the syntax: $ kill kill: usage: kill [-s sigspec | -n signum | -sigspec] pid | jobspec ... or kill -l [sigspec] $
2
votes
2answers
303 views

Is there a good FOSS utility for converting machine code to assembly or even C?

If I buy a piece of x86 32-bit or 64-bit software but I don't receive the source code, and I need to modify the software, I'll need to convert the machine code back into a high level language or at ...
2
votes
1answer
2k views

I try to add passwords to the “pass” password manager. But my attempts fail with “no public key” GPG errors. Why?

I am trying to install Pass: the standard Unix password manager, however, when I try to add passwords to the appliation I get these errors gpg: Kelly's Passwords: skipped: No public key gpg: [stdin]: ...
3
votes
1answer
234 views

Understanding the output of the “who -a” command

I ask this question because, while there are many answers on the internet showing that "who -a" is an option, nobody explains how to read the output. If you can provide a link to an online site that ...
1
vote
2answers
252 views

Clear the screen and show a banner

I need a text banner on a screen which is projected all the time. The screen is connected to a PC with tmux on it. Example of text "banners": figlet $(fortune) or toilet "$(cowsay $(fortune))" ...
0
votes
1answer
166 views

Change Directory and List Files [duplicate]

Possible Duplicate: Make cd automatically ls I think that it would be very useful to have a unix utility that combines 'cd' and 'ls' so that when you change your directory, it automatically ...
9
votes
3answers
461 views

Doing two things with output from a command

I have a program texcount that outputs the number of words in my LaTeX document. I can also pipe the output of this to sed to make the newlines TeX linebreaks and write this to a file which I can then ...
3
votes
2answers
465 views

Are there any utilities to quickly add, list and remove command aliases?

I'd like to be able to quickly, on-the-fly add (and list/remove) command aliases so that they persist between shell restarts (as if they were added to .bashrc). Are there any ready ...
3
votes
1answer
127 views

Colour problem when capturing a png of the top panel of the screen

I want to capture a window as a png from within a bash script, using the window's ID. In this case, the window is the top panel.  Using gnome-screenshot the colours are true, as per this image... ...
3
votes
2answers
189 views

Peer to peer~ish LAN storage

I have a distributed application that consists in a main CMS server where "human" users can upload videos, pictures (media content, basically) and a bunch of "players" that play those videos or ...
5
votes
1answer
2k views

Are there alternatives for `dd`?

What other tools should I use to read and write files with truncation, seeking and skipping. dd's command line options seem inconvenient and foreign and I don't like choosing between slow, but precise ...
22
votes
4answers
994 views

Are Linux utilities smart when running piped commands?

I was just running a few commands in a terminal and I started wondering, does Unix/Linux take shortcuts when running piped commands? For example, let's say I have a file with one million lines, the ...
4
votes
3answers
616 views

Monitor directory and if a file is requested then rsync on demand

Is there a tool that monitors a certain directory and if a program tries to access a file in that directory, the program loads that file from another place transparent for any application that tries ...
12
votes
2answers
275 views

`test` and `[` - different binaries, any difference?

I noticed while answering another question that test and [ are different binaries, but the [ manpage pulls up test's. Besides the requirement for an ending ], is there any difference? If not, why are ...
1
vote
1answer
716 views

How to change the default line length for od and hexdump

Is there any way to change the default line length for the od and hexdump commands? Can't see anything apropriate in the man pages.
0
votes
3answers
135 views

CLI & Markup language

I often find myself editing files for my personal use that are plaintext. Either those are notes, annotations in project directories or sometimes the output of programs that I annotate. However, ...
2
votes
2answers
3k views

List of available command options?

I'm currently setting up my first web server without a control panel and so far things are going pretty good! I was just wondering if anyone could direct me to somewhere that explains all of the ...
1
vote
3answers
220 views

line count on all the PHP scripts within my webroot with wc

How can I do a line count on all the PHP scripts within my webroot? I am trying something like this below to no avail: wc -l *.php
2
votes
1answer
1k views

Listing a hardrive partition by blocks using LBA

Most hard drive and partition inspection tools seem to list the items using sectors, head.. etc. From another question I was told that these are virtual because they have to be converted from lba, ...
2
votes
4answers
294 views

xsel < /tmp/xselection not working in script

I'm trying to use the following script: #!/usr/bin/env bash # Edit xselection in gvim xsel > /tmp/xselection gvim /tmp/xselection xsel < /tmp/xselection But the final line does not seem to be ...
3
votes
2answers
226 views

ln gives different results when run multiple times

I have this simple script to use with seventh sense (it's a lone wolf gamebook reader/player): #!/bin/bash GAME_PATH=$(dirname "$(readlink -f "$0")") SEVENTH_SENSE_PATH=$(echo ...
4
votes
3answers
1k views

Why doesn't uname -a return a useful identifier

I typed the command uname -a into my college's server and got this: 2.6.18-274.3.1.el5 #1 SMP Tue Sep 6 20:14:03 EDT 2011 i686 i686 i386 GNU/Linux Are they trying to hide the version of Linux that ...
6
votes
1answer
393 views

Interactive tree command

Is there any version of tree command that displays file structure as a tree structure, but in a way that I can interactively walk trough? Why do I need it exactly - I am trying to simulate TextMate ...
4
votes
2answers
4k views

file block size - difference between stat and ls

I've noticed that when I do a: ls -ls file It provides block count, say 8 blocks. When I do: stat file I notice that the block count is 16, twice the number given by ls. The block size on my ...
2
votes
1answer
754 views

How to plot the output of a command

How can I plot the output of this command line with GNUPlot? What should the diagram script look like? I want a histogram. wget -O - -o /dev/null http://www.stackoverflow.com/ | cat | cat | sed ...
4
votes
2answers
2k views

Set alignment of numeric columns when columnating data

I use column -t to format data for easy viewing in the shell, but there seems to be no option to specify column alignment (e.g. align to the right). Any Bash one-liners to do it? I have arbitrary ...
3
votes
2answers
96 views

Output the changes to a log file

If I use tail -f *filename* I get a real nice display of whatever is changing in a given file. However, sometimes I want to be able to search this text or otherwise look it over slowly. Is ...
9
votes
4answers
7k views

creating a sequence of numbers, one per line in a file

Is there a way to create out of thin air, a file that is a sequence of numbers, starting at a given number, one per line? something like magic_command start 100 lines 5 > b.txt and then, b.txt ...
9
votes
2answers
20k views

How can I test the encoding of a text file… Is it valid, and what is it?

I have several .htm files which open in Gedit without any warning/error, but when I open these same file in Jedit, it warns me of invalid UTF-8 encoding... The html meta tag states ...
3
votes
1answer
1k views

installing column unix utility on windows

I would like to be able to use the BSD unix utilities: column, join and paste in my Cygwin installation. It seems that they are not available, or I cannot find them. Is there a way to install them so ...
2
votes
1answer
1k views

How synchronize two disks (or folders) using symbolic (or hard) links (like rsync)?

I'm searching a tool or a shell script or another program to synchronize two or more folders or disks. But it differs of rsync tool, because, I don't want to duplicate the missing file, but do a ...
2
votes
1answer
84 views

How to use the -t option of Unix command look

I'm learning the look utility and I don't understand the meaning of the -t option. Can someone show me some examples of it? I read the man page, but still don't know what it exactly means.
3
votes
2answers
105 views

Unatended script execution in ubuntu terminal

I have installed Ubuntu on a VMWare virtual machine. When I got to installing a VMWare tools, I have stumbled upon a simple question: If I execute a script (perl script in VMWare tools case), is ...
5
votes
1answer
141 views

How would one detect if external command exists in a script?

Is there a way to detect if an external command exists (i.e. wget, svn)? More specifically today, i was trying to run one of my scripts i wrote and the person didn't have wget or svn installed. The ...
0
votes
0answers
30 views

Problem with calling program from the command line [closed]

Note: this is a cross post with this post on SO. I am trying to build a command line wrapper in Python 3 for an exiting command line tool called 'spooky' and I am having a hard time understanding ...
0
votes
1answer
363 views

Listing only the files in a folder and inside its subfolders

Is there a linux command for getting only the files in a folder and inside its subfolders? I have used the find command, but it is displaying all the files and folders. I am executing this shell ...
35
votes
4answers
5k views

What is the difference between a builtin command and one that is not?

Is there any intrinsic difference between a builtin command and another command which can nominally do the same thing? eg. Do builtins get "special" treatement? ... is there less overhead running ...
1
vote
3answers
706 views

How to determine which executable on my path will be run?

I run which and get the following, brendan$ which python /opt/local/bin/python brendan$ which -a python /opt/local/bin/python /usr/bin/python brendan$ ls -l /opt/local/bin/python lrwxr-xr-x ...
1
vote
1answer
566 views

Good “progress bar” about md5sum checking progress?

I'm using this right now: time md5sum -c *.txt | pv | grep -v ': OK$' but aren't there any smart solutions that can list that how many files haven't been checked? I mean I have many md5sum's in ...
4
votes
3answers
481 views

General specification for command line interface

I was wondering where I can find and learn some general idea about the command line interface used in Linux and bash? As to now, I have found pieces of such information only from experience, such as ...
1
vote
3answers
347 views

Sort data on multiple columns

INPUT (unsorted, bad) "XYZ-ZTE-43255 serverB618 agreed","XYZ-ZTE-44432" ,"XYZ-ZTE-43255" "XYZ-ZTE-52775 serverB110 agreed", "XYZ-ZTE-79213 - serverB688 agreed", "XYZ-ZTE-77323 serverB617 agreed", ...
4
votes
2answers
237 views

Why do I get a 'conformability error' when I attempt to convert water in GNU units?

I've been using the GNU units program and I seem to think that I should be able to convert water between a volume and a weight. Examples: You have: 1 gram water You want: cm^3 conformability error ...
5
votes
2answers
1k views

Combine input from multiple files/pipes without clobbering lines or blocking?

Is there a tool that will take input from multiple files or pipes and write it to stdout, without blocking on reads, such that individual input lines come out intact? I basically want to multiplex a ...
1
vote
1answer
2k views

e2fsck progress bar?

How can I see the progress of e2fsck in the terminal? Are there any pv like ways? For example how can I see how far along this command is in progress: e2fsck -f -y -v /dev/sdb1
4
votes
2answers
880 views

Why is bash completion of a symlink different than a directory?

I usually do a find with an environment variable as the path when searching for source code. Recently I replaced my environment variable with a symbolic link, and it broke Bash's shell completion. ...
15
votes
3answers
3k views

Why use superflous dash (-) to pass option flags to tar?

To create a tar file for a directory, the tar command with compress, verbose and file options can be typed thus: $ tar -cvf my.tar my_directory/ But it also works to do it this way: $ tar cvf ...
2
votes
1answer
47 views

Explain the output of -D rates in GNU find

I did ~/pythonsource1/python2.6-2.6.5$ find -D rates . -type d and got Predicate success rates after completion: [need type] -type d [0.4] [280/4350=0.0643678] -a [0.4] [280/4350=0.0643678] ...
2
votes
1answer
514 views

ntop versus mrtg

I'm evaluating tools for measuring network activity and although mrtg seems to be the most highly regarded, I'm really impressed by ntop. Are there any reasons that mrtg is preferred to ntop?
1
vote
1answer
78 views

Good base converter or help using gbase?

Dear all, Could you suggest a good base converter that also does "signed" conversions? Either gbase does not do it, or I can't see how it's done. Any help would be great. What I want to do is give the ...