3
votes
1answer
41 views

What is 'ls quote'?

Today I happened to press ' after ls So the command is ls' After I issued this command: [edit]Seems the image can't display properly > ls' quote> ls' zsh: command not found: ls\nls > ...
13
votes
3answers
2k views

Why isn't there any shell command to create files?

Attention please: I am not asking how to make a file from the command line! I have been using touch for making files for years without paying attention that its main purpose is something else. If ...
15
votes
6answers
2k views

Why do I have to cd out of a deleted directory?

On my server I have a directory structure looking something like this: /myproject/code I normally have an ssh connection to the server and 'stand' in that directory: root@machine:/myproject/code# ...
6
votes
3answers
468 views

What is the difference between the use of ; and executing a script

I'm using bash as my main shell, but it's an open question and responses for shells others than bash are very welcome. If I'm typing interactively #original line #wget http://something.com ...
8
votes
3answers
203 views

How to execute a command repeatedly with different arguments?

I'm on Ubuntu. I copied some arguments (separated by newline) and I can use xsel to print them out like this $ xsel arg1 arg2 arg3 arg4 ... Now, I want to use each of these arguments for another ...
1
vote
1answer
71 views

Command works with tilde at the end. How?

I'm on Ubuntu. I have a script called myscripts in /usr/bin/myscripts This script simply changes the current directory to ~/Work/MyScripts Normally, I simply open a terminal and type ~/Desktop$ . ...
1
vote
1answer
289 views

Exit of “> ” mode in Unix shell

In sh (not Bash), how would we abort execution of command when the prompt is in > mode? For example, when entering a string with quotes only at the beginning, it makes the prompt look like >, ...
1
vote
7answers
133 views

what are some uses of .(single period) & ..(double period) in the shell command line

The single period . means current working directory The double period .. means parent of the current working directory I can only think of . being used in relative pathname etc cd ./bin/usr How are ...
2
votes
1answer
82 views

When should you use subshells vs `xargs`?

Many simple commands using xargs could be rewritten as commands using subshells. For instance, here is something I was using earlier today, to concatenate the ten largest binaries in /usr/bin, written ...
2
votes
1answer
67 views

Copy files based on date/time from subset of directories

I'm teaching a class where (~80) students are submitting assignments that I can access via webdav, organized by student in directories named by their unique identifier. The students are split into ...
9
votes
2answers
182 views

How can I redirect `time` output and command output to the same pipe?

Suppose I have a binary called foo. If I want to redirect the output of foo to some other process bar, I could write ./foo | bar. On the other hand, if I wanted to time foo, and redirect the output ...
4
votes
2answers
132 views

Dump process's stdin and stdout

I have two processes, let's say Parent and Child. Parent launches the Child and communicates with it through child's stdin and stdout. Parent <-> Child These processes use text protocol and I ...
3
votes
7answers
387 views

Batch renaming of files [duplicate]

I have a directory full of images: DSCN4749.JPG DSCN4750.JPG DSCN4892.JPG ... And I would like a one-liner to rename them to (say). dscn4749.jpg dscn4750.jpg dscn4892.jpg ... How do I do this? ...
2
votes
4answers
84 views

Incrementing a variable each time the system boots up

The idea is to initialize a variable and set it to 0. Then create a script that executes on boot and increments that variable by 1 each time the system boots up again. Sounds simple enough right?
6
votes
5answers
741 views

How does one find out how many bits a file has in one command?

I know I can use ls -lat to find out how many bytes has a file and then multiply by 8 to find out how many bits. But is this possible in only one command line?
0
votes
1answer
38 views

How to escape spaces while using command's output in command line [duplicate]

I want to perform the following command in command line : $ md5sum $(find . -type f) But this would cause problems when it encounter files with spaces in filenames : md5sum: Kaufmann: No such ...
2
votes
3answers
110 views

Preserving color output with cut

Using bash interactively I am trying to use cut to prevent the lines from going longer than my terminal width. But when using a command with colorized output all the color gets removed by cut. For ...
0
votes
3answers
100 views

How to compact a chmod UNIX command

Is there anyway to compact the follow UNIX command: chmod 755 scriptA.ksh | chmod 755 scriptB.ksh | chmod 755 scriptC.ksh | chmod 755 scriptD.ksh The above command makes every KornShell (ksh) ...
0
votes
0answers
20 views

Multiply 2 array index variables shell programming [duplicate]

How do i multiply 2 array index variables given the following foo=(1 2) bar=(0.1 0.2) foobar=$((foo[1]*price[1])) # this is wrong echo "$foobar" Current output : 0 Correct/Expected output : 0.4
0
votes
2answers
62 views

zsh: What does the command “time + number” do in zsh

When I type time + number in zsh: # atupal at local in /tmp/atupal/setup/bin [10:01:49] $ time 1 /tmp/atupal/setup/bin/lib/python2.7 # atupal at local in /tmp/atupal/setup/bin/lib/python2.7 ...
3
votes
3answers
163 views

How to move the first x files

I have this huge folder with thousands of unordered files. Is it feasible to move the first 5000s to a subfolder via the mv command? For now I move files with mv *some_pattern* ./subfolder1/ ...
1
vote
2answers
70 views

Removing “[crap-like-this]” from strings using bash parameter expansion?

If I have the following $STRING aaa.bbb.ccc.[ddd].eee.fff.[ggg].hhh is there any way, using bash parameter expansion, to echo the following aaa.bbb..ccc.eee.fff..hhh That is, remove all ...
7
votes
2answers
114 views

what is `env <command>` doing?

What is the command env ls -al doing? I had a Linux test and there was question: "How to run command directly, but not its alias?" I knew that there exists solution like prefixing command with some ...
3
votes
4answers
122 views

How do you find what keys the “erase” and “line-kill” characters are in Ubuntu?

I'm new to Unix and have bought today a copy of "The Unix Programming Environment". I'm trying out the stuff from the book. But some of them are not working as expected like : To kill a line and ...
3
votes
1answer
65 views

Getting size of directories and exclude some folders

I have an directory structure like this: application1 application1_edit application2 application2_edit Is there any way to get the total size for every folder (including sub-directories) and ...
1
vote
2answers
77 views

Using globbing/wildcards when Opening Files from Terminal

I have a folder A. Inside the folder, there are some files a,b,c,d and there is a subfolder, B, containing files e,f,g. Suppose I want to open files a,b,c,d: then I just type xdg-open *. However, ...
0
votes
2answers
76 views

Using Pipeline to Direct Files to Program that Opens Them

I have a Music folder, in which I have some music tracks, which aren't organized too well. Thus, if I want to find a particular track, I usually type: ls Music | grep <keyword>, where ...
2
votes
1answer
46 views

Piping fragments of a document through various commands

I want to send, maybe using escape sequences such as $$$, fragments of an article through various commands, possibly with modifiers. The stdin would be replaced by the corresponding stdout. (Deleting ...
0
votes
1answer
96 views

How to pass wildcards in command line [closed]

So this works: foo -a -b -c "path/file.ext" And this too if I want to pass all files from directory: foo -a -b -c path/* But if I add the quotes foo -a -b -c "path/*" It doesn't work anymore: ...
2
votes
1answer
71 views

Any better method than this for sorting files by their creation date?

I needed to display a list of directories sorted by their creation date and I came up with this code snippet that I thought was kind of clever. Is there a more obvious way to do this that I'm missing? ...
13
votes
3answers
1k views

Find out current working directory of a running process?

What command(s) can one use to find out the current working directory (CWD) of a running process? These would be commands you could use externally from the process.
5
votes
6answers
361 views

What is the easiest way to add a string on the beginning of every line of the file from the command line?

I am looking for a way to add some string to the beginning of every line (same string for every line). Not something customizable but rather something that will be easy to remember and available on ...
1
vote
1answer
77 views

What is the use of ; in a single line command?

What does ; mean in single line scripts like this: while true; do sudo -n true; sleep 60; kill -0 '$$' || exit; done 2>/dev/null & Does it mean new line, or "next command"?
3
votes
3answers
519 views

Merging two directory without copying the files

Let's say I have as follows : Folder A C1 file a A2 Folder B C1 B2 file b B3 What I want is to merge these two folders, which would give me : Folder C ...
2
votes
2answers
188 views

Using calibre from the command line

Using calibre from the command line, in debian testing, how can I insert a tag with the syntax being ebook-meta ebook_file --tags rhubarb but for a range of files, but all by the same author ...
-1
votes
1answer
249 views

How to create a GUI in shell script without any third party libs just like setup command [closed]

How to create a GUI in shell script without any third party libs (like setup command)
2
votes
3answers
716 views

Remove ^M character from log files

Remove ^M character from log files. In my script I redirect output of my program to a log file. The output of my log file contains some ^M (newline) characters. I need to remove them while running ...
4
votes
4answers
595 views

Why cat, grep and other commands can't understand files starting with minus sign? [duplicate]

If I have a file which name starting with single or several minus sign, for example --1 it can't be used as a parameter of many commands. Even if I run cat --1 instead of file content I get ...
8
votes
2answers
559 views

What is meant by a shell is in “vi” mode or “emacs” mode?

This question follows directly from the answer to one of my previous questions here. I am newbie to unix world and this site has helped a lot to understand some core concepts. In this case I am ...
3
votes
2answers
77 views

Can I run a command after the user uses Ctrl-C to kill a command?

So at my position we use a shared set of aliases to do builds. Something like... alias 'build'='cd $BUILD_ROOT; m; cp ...; cp...; deploy; deploy; deploy; cd -' This is super irritating because the ...
2
votes
2answers
81 views

How can I execute a shell script that exists in a longish path with a single command without first cd'ing to the directory?

In Linux I always cd to a longish path and then run the script: cd /scratch/someDir/someOthernestedDir/ ./shellscriptName.sh How can I avoid achieve typing this longish path and then executing ...
1
vote
2answers
244 views

Getting specific line from terminal output

"Hmm, I need to edit file-i-must-edit-2, but I cannot remember where it is." locate file-i-must-edit /home/user/file-i-must-edit-1 /home/user/file-i-must-edit-2 /home/user/file-i-must-edit-3 ...
0
votes
2answers
172 views

How can I make “bind” command to work in sh shell

How can I make the next script to run when I'm using sh shell: #!/bin/bash bind '^[[3'=prefix-2 bind '^[[3~'=delete-char-forward bind '^[[1'=prefix-2 bind '^[[1~'=beginning-of-line bind ...
1
vote
2answers
321 views

How do I run a command on multiple files

This is pretty basic, I have a folder with several subfolders of JS files and i want to run Google's Clojure compiler on all of the files in those folders. The command to process a single file is as ...
2
votes
1answer
102 views

Is there a text-only equivalent (no curses) of `zenity --question`?

For my mercurial commit hook, I want to run my test cases and be asked whether I really want to commit if any of the tests fail. I'm thinking something like <run-the-tests> || ...
4
votes
2answers
146 views

Is it possible to restrict certain commands from being run in a directory?

I have two directories: src and projects. I would like to prevent myself from running git ... unless I am specifically inside src or projects. Is this possible?
1
vote
0answers
49 views

add audio from playing file to microphone stream

I need to add a sound to what the microphone is capturing, is it possible? I started with man aplay and found that I can do aplay -D PCMdevice filepath.wav so then I listed the PCM devices with ...
1
vote
2answers
782 views

What does the tilde (~) mean at the end of a filename? [duplicate]

What is the file with the ~ at the end of the filename for? $ ls # aliased to add flags -rwxrwxr-x 1 durrantm 2741 May 16 09:28 strip_out_rspec_prep_cmds.sh~* drwxrwxr-x 13 durrantm 4096 May 16 ...
4
votes
1answer
44 views

Suspend and edit previous single line commands

Say I want to modify the latter of some concatenated command line options, is it possible without killing the first command? Specifically I have compile and run scripts executed thusly: > compile ...
3
votes
3answers
509 views

Count number of lines of output from previous program

I'm trying to count the number of lines of output a certain program produces. The problem is, the program takes a long time to run, and I want to display the output to the user. Is there a way to ...