One or a set of directives issued in the *nix environment to get information, change the state of something or to execute something. In other words: To gain an objective.

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3
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2answers
448 views

Please explain the -f option in pgrep

man pgrep says the following about -f option: -f The pattern is normally only matched against the process name. When -f is set, the full command line is used. What does it ...
4
votes
1answer
772 views

What is the difference between exiting a process via Ctrl+C vs issuing a kill -9 command?

I know I can kill any process with kill -9 command . But sometimes i see that even if I have terminated a program with CTRL+C , the process doesn't get killed . So I want to know the difference ...
0
votes
2answers
13k views

Please explain this output of ps -ef command?

A part of the output from the ps -ef command is given below : UID PID PPID C STIME TTY TIME CMD root 1 0 0 2012 ? 00:00:01 init [3] root 2 ...
3
votes
3answers
8k views

What is the difference between ps and top command?

What is the difference between ps and top command ? I see that both can display information about running processes . Which one should be used when ?
13
votes
4answers
902 views

What is the difference between running a executable just by name and by appending a dot /slash before it?

This is the output from ls -all command : -rwxr----- 1 subhrcho dba 3600 Nov 13 17:26 jdev -rw-r----- 1 subhrcho dba 1566 Nov 13 17:26 jdev-Darwin.conf -rw-r----- 1 subhrcho dba 347 Mar 6 2009 ...
2
votes
1answer
527 views

Please explain the output from the jobs command

When I ran jobs command I see the following output : [1] - Suspended ./startWebLogic.sh [2] + Suspended (signal) top What does -/+ indicate in the second column ? ...
1
vote
2answers
346 views

explain the command `printf — “#!${opt_E}”`

I am not able to understand this command and getting confused : here are things i executed on linux trying to undertand its working [root@testgfs2 final_scripts]# printf -- "#!${opt_E}" printf -- ...
3
votes
2answers
389 views

Make copies of a single directory to multiple directories with different names

I'm trying to replicate a single directory (with sub-directories) to a bunch of new directories based on a list. For example I can: mkdir Fred Barney Thelma Louise Foo Bar How would I copy a premade ...
5
votes
1answer
2k views

What is the use of literal command in ftp?

Browsing through FTP help (i.e. ftp> ?), showed me a command name literal, description of which is ftp> ? literal literal Send arbitrary ftp command I tried to do some trial and ...
8
votes
3answers
1k views

Difference between commands in bash script and commands in terminal

Are there any differences between commands that you type into the terminal and commands you include in a script?
5
votes
2answers
515 views

Why is cd not a file in /bin? [duplicate]

Possible Duplicate: Why is cd not a program? I noticed that every other commonly used util, like ls, cp, rm, etc. are actually files in /bin -- but cd is not. Nor is it in any other ...
4
votes
5answers
103 views

unix command to print till 3rd occurence of “/” in each line

I have one file contains data as follows... /tutordashboard/manageTutorLogInStatus/?ua=TQ-AUTOCLOSE-REENTER&filterId=089089087087080&dt=1325757272 ...
21
votes
2answers
683 views

What is `--` called?

Recently I got to know of -- that is double-hyphen which is used to tell a command that the option list has ended and what follows should not be considered as a option. So, grep -- 'search_word' * ...
1
vote
1answer
187 views

What does - mean with association to Linux files and directories [duplicate]

Possible Duplicate: What does “--” (double-dash) mean? What does '--' (two dashes) mean with association to Linux files and directories. I've found something else but not too sure if it is ...
3
votes
0answers
83 views

gnu screen: automatic session on split

Inactive region appears after 'split' command in gnu screen now. You must go to the new region and type :screen. Only after that shell session appears in this region. Is it possible to make new ...
3
votes
2answers
2k views

Difference of folders and files

I have two folders which have different folders inside. Those folders also contains different files. I am looking for the command that would give me the difference between those two parent folders. ...
1
vote
2answers
8k views

tar: Unexpected EOF in archive

I am trying extract .tar.gz file it but with no luck gzip: stdin: unexpected end of file tar: Unexpected EOF in archive tar: Unexpected EOF in archive tar: Error is not recoverable: exiting now the ...
5
votes
3answers
5k views

Why doesn't ln -s tell that it fails when creating a symlink to an existing symlinked directory?

When running (on linux different ubuntu variations): >ln -s dir_1 symlink_dir >ln -s dir_2 symlink_dir It fails without telling that it fails. But if you do the same thing on a file instead ...
0
votes
1answer
415 views

Command not found

I am trying to stop a syslog using chkconfig but bash says that command is not available. But when I do man chkconfig it opens man page. This is the command i'm trying to execute. ...
5
votes
3answers
3k views

Test command in unix doesn't print an output

When I type this in the terminal test 4 -lt 6 I don't get any output. Why not? I need that 0 or 1
8
votes
2answers
3k views

What's the difference between “dir” and “ls”?

I have compared the man pages of dir and ls and they seem to be exactly the same. Both are part of GNU coreutils and "list directory contents". The only difference I've seen so far is that dir ...
34
votes
2answers
2k views

What is the point of the `cd` external command?

As referenced in this fine answer, POSIX systems have an external binary cd in addition to the shell builtin. On OS X 10.8 it's /usr/bin/cd. You can't use it like the builtin cd since it exits ...
13
votes
5answers
59k views

How to move all files and folders via mv command

How can I move all files and folders from one directory to another via mv command?
5
votes
1answer
1k views

Command & binary exists but cannot be executed

I transfered /etc/* files from one Linux server to another and now I have a strange error. Both are Debian Squeeze. When I run a command, e.g. ssh, I get an error: bash: /usr/bin/ssh: No such file ...
2
votes
1answer
532 views

Computer speed in flops

Nowdays, The speed of supercomputers are measured in Flops. Is there any linux command or tool that can calculate or gives the speed of a processor in Flops. If not, than how do we measure it.
2
votes
2answers
2k views

Where to find the source code for ps?

I want to check out the source code for commands such as ps. It seems to be impossible to search LXR (linux.no) for "ps". Where do I find it?
4
votes
3answers
4k views

Split command output by linebreak?

I have a command returning multiple lines. For further processing I need to process each single line of those lines. My current code works by modifying the IFS (Internal Field Separator): ...
17
votes
2answers
3k views

The “yes” command

There is a yes command in unix/linux which basically infinitely prints y to the stdout. What is the point of it, and how is it useful?
4
votes
4answers
772 views

Is there a practical use for the GNU factor command?

Looking through the GNU Coreutils, I spotted the factor command, that I had never noticed before. Reading the man page: Print the prime factors of each specified integer NUMBER. If none are ...
20
votes
2answers
10k views

How to run time on multiple commands AND write the time output to file?

I want to run time command to measure time of several commands. What I want to do is: Measure the time of running of all of them added together Write the time output to a file Write the STDERR from ...
5
votes
1answer
1k views

Git auto-complete

I am using Git as many of you do. Also, I don't use any GUI for that — just CLI. So I was wondering: are there any way to make Git commands (git status, git checkout etc.) complete themselves when ...
3
votes
1answer
1k views

How to check will my computer is going to reboot(or shutting down)?

When I send a reboot command(or shutdown) command to a Linux machine does it keeps that messages at somewhere and can I query it. I.e. I will send a reboot command and after that I will run another ...
0
votes
1answer
95 views

Why does this compound command report errors when copying directories? [duplicate]

Possible Duplicate: Why does this compound command report errors when copying directories? if one executes the following two commands in one line, as follows, rm -rf dir ; cp -r dir2 ...
0
votes
2answers
209 views

Why does this compound command report errors when copying directories?

if one executes the following two commands in one line, as follows, rm -rf dir ; cp -r dir2 dir it may complain that cp can not create directory dir/subdir: File exists but if these two commands ...
1
vote
3answers
313 views

Print folders names character count

I am trying to use find . -type d -print | wc -m where -m or --chars would print the character counts of the folder names. Take following screen shot as example, the character count for tempFolder + ...
6
votes
3answers
644 views

Get a list of 3 letter commands on Mac OS X

How can I either create or find a list of 3-letter unix commands on Mac OS X? I'd like to create a new program/command for a project. I'd like to make it a 3-letter name, but I don't want to conflict ...
-1
votes
1answer
2k views

Check if the command exists in bash

I want to check if a given command exists in bash and I care only about the native commands of the bash and not the scripts written by the user. When I refer to native commands I mean all those ...
3
votes
2answers
843 views

is there any command like “wall” that runs a “command” in all terminals

as you know "wall" command sends a message to all terminals: wall message now my question is this: is there any command that can send a "command" to be run in all terminals? for example sending ...
3
votes
1answer
2k views

Make awk use bash with the system() command

Is there a way to make awk use bash instead of sh when running system commands using the system() call? I want to use some bash-specific features such as [[ ]] and < > string comparison operators: ...
7
votes
2answers
7k views

Execute command in remote active terminal

Suppose you have a terminal emulator (T1) open with a PID of 6350. From another terminal, type this command (C1): echo "ls\n" > /proc/6350/fd/0 This writes ls and the new line in T1 but does ...
5
votes
3answers
826 views

Linux Rename File Beginning with “--” [duplicate]

Possible Duplicate: How do I delete a file whose name begins with “-” (hyphen a.k.a. dash or minus)? This is an awkward one, I have received some files from a windows machine ...
88
votes
6answers
8k views

Why is cd not a program?

I've always wondered why cd isn't a program, but never managed to find the answer. Anyone know why this is the case?
1
vote
1answer
284 views

How to active tabs on windows by terminal? wmctrl doesn't have option available

I'd like improve a script of mine that uses firefox to perform tasks. I need activate a window and a tab with a specific name. For example, the window name could be Mozilla Firefox and the tab ...
3
votes
1answer
853 views

Searching a file & excluding lines with a specified string

I have a large log file that contains numerous lines of the same entry, lets call it "repeat-info". As an example here is what a portion of the log might look like: [Timestamp] repeat-info ...
20
votes
3answers
955 views

Which are the standard commands available in every Linux based distribution?

I would like to know which are the standard commands available in every Linux system. For example if you get a debian/ubuntu/redhat/suse/arch/slackware etc, you will always find there commands like: ...
1
vote
3answers
191 views

how to forbid a command without a permission

I intended to delete all the backup files in a directory, so I was going to type rm *~ in the terminal. Unfortunately, I hit the Enter before hitting the tilde and unhappy things happened. Although, ...
4
votes
2answers
4k views

How to execute one command on all files within a folder

Saying, I have this tree and I want to execute ruby on all scripts within the folder. How could I archive through one line of command. ./ ../ rb-script/ sample1.rb sample2.rb
2
votes
1answer
861 views

how to get out from the command iostat on unix?

I was installing a .iso 8,2 version in a vmware to learn unix., and i am stuck with iostat command, i run iostat 3 and is keep going to show me the results, but whem i put exit or q or q! to exit, he ...
6
votes
3answers
5k views

What is the purpose of -e in sed command?

I can't find any documentation about the sed -e switch, for simple replace, do I need it? e.g. sed 's/foo/bar/' VS sed -e 's/foo/bar/'
4
votes
5answers
2k views

Execute string result from shell script as a set of shell commands

I create a string result from my shell script and i want to execute it as a shell command. For example file_a is: user1@gmail.com user2@gmail.com script: awk '{print "mail -s \"welcome\"", $1}' ...