The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks.

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9
votes
6answers
128 views

How do I source another process's environment variables?

If I examine /proc/1/environ I can see a null-byte-delimited string of process 1's environment variables. I'd like to bring these variables into my current environment. Is there an easy way to do ...
0
votes
2answers
30 views

ln -s with a path relative to pwd

I'm trying to create a bunch of symbolic links, but I can't figure out why this is working ln -s /Users/niels/something/foo ~/bin/foo_link while this cd /Users/niels/something ln -s foo ...
22
votes
5answers
1k views

How does clear command work?

I was recently trying to learn more about how the shell works and was looking at how the clear command works. The executable is located in /usr/bin/clear and it seems to print out a bunch of blank ...
7
votes
6answers
593 views

Is it possible to remove folder prefix from a `ls` command

I am in a bash script and I want to get the list of all files (let say all jar files). I execute the command ls -1 lib/*.jar and I get the output: lib/mylib_1.jar lib/mylib_2.jar ... Is there any ...
6
votes
1answer
86 views

How to specify additional parameters for GNU sort's --compress-program option?

sort --compress-program=/bin/gzip works fine, but how can I pass options down to the compression programm (e.g. --best or --fast)? sort --compress-program=/bin/gzip\ --best failes with the error ...
3
votes
3answers
131 views

Rescue value from second last line

After I run a script, I've got the following lines: PyMOL(TM) Molecular Graphics System, Version 1.4.1. Copyright (c) Schrodinger, LLC. All Rights Reserved. Created by Warren L. DeLano, ...
1
vote
1answer
144 views

What is the extended version of the “sl” command?

Recently I've been discussing Unix humor with a friend and we got to the topic of the sl command. I got the sources, compiled, installed on our development machine, and... got rather disappointed. The ...
4
votes
4answers
87 views

`ls -l` of a file and all the directories leading to it?

Before I start writing a (probably easy) script, is there a command that does the equivalent of the following one: [:~/software/scripts] % ls -ld / /usr /usr/bin /usr/bin/tee drwxr-xr-x 21 root root ...
2
votes
2answers
264 views

How to open process substituted file from php?

Here's what I tried to do myself: $ type 1.sh #!/bin/bash -eu php -r 'var_dump(file_get_contents($_SERVER["argv"][1]));' -- <(echo 1) $ ./1.sh PHP Warning: file_get_contents(/dev/fd/63): failed ...
1
vote
1answer
23 views

Easiest way to mount Google Cloud Storage in CentOS

we use centos for some hosting projects, but nut very expertise with systems. We pretend to use a main CentOS box to mount an "unlimited" Google Cloud Drive and then share it via NFS to the rest of ...
14
votes
3answers
4k views

make my zsh prompt show mode in vi mode

I use bindkey -v (for bash-ers set -o vi I think that works in zsh too) or vi(m) mode. but it bugs me that I don't have any visual cue to tell me whether I'm in insert mode or command mode. Does ...
2
votes
10answers
603 views

How do I run the same linux command in more than one tab/shell simultaneously?

Is there any tool/command in Linux that I can use to run a command in more than one tab simultaneously? I want to run the same command: ./myprog argument1 argument2 simultaneously in more than one ...
3
votes
1answer
33 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 ...
5
votes
3answers
392 views

What is the difference having double quotes or not in bash [duplicate]

I have some bash scripts, one which has the following content: #!/bin/bash source $(dirname ${BASH_SOURCE[0]})/script.sh while the other one has the following content: #!/bin/bash source ...
0
votes
2answers
68 views

How do I run a command on a TTY from a SSH session?

Does anyone know of a way that I could run a command from my ssh session and have it display on tty1? It seems like I could do that like: script command >> /dev/tty1. However, if I were to do ...
2
votes
1answer
345 views

Gnome + Linux: GUI apps don't inherit PATH from parent console apps

In Gnome, don't GUI applications inherit the PATH of the shell process that launches them? Apparently, GUI applications see only the PATH specified in ~/.profile. No issues with console applications, ...
0
votes
0answers
11 views

Convert rgba color value to a Terminal supported color

Randomly I will take the following example: rgba(122, 143, 186, 0.54) How can I convert this color to the closest Terminal supported color?
2
votes
6answers
120 views

When does a shell get executed during the linux startup process

I do not understand when does a shell, lets say bash, get executed, which program runs bash initially first.
1
vote
2answers
40 views

About escape with SSH pipe

I want to execute the awk command with long parameters,like this: ssh host "netstat -rn|awk 'NR!=1 && NF>=6 && $1!="Destination" {printf "%-15s %-20s\n", $1, $2}'|sort -f " but ...
10
votes
6answers
495 views

How can I cleanly add to $PATH?

I'd like a way to add things to $PATH, system-wide or for an individual user, without potentially adding the same path multiple times. One reason to want to do this is so that additions can be made ...
19
votes
11answers
2k views

Remove duplicate $PATH entries with awk command

I am trying to write a bash shell function that will allow me to remove duplicate copies of directories from my path environment. I was told that it is possible to achieve this with a one line ...
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 > ...
1
vote
3answers
63 views

How to display “human-readable” file sizes in find results?

I'm trying to find all large files on my Centos server. To do that I'm using: find / -maxdepth 10 -size +100000 -ls I tried changing -ls to -lsh but it is not allowed. How can I display these ...
1
vote
1answer
40 views

Linux : how to redirect stdout & stderr to logger?

I have a program I need to run at startup, it has output on stdout and stderr that I want to redirect to the system log using the logger command. What I have in my startup script is thie: ...
8
votes
4answers
209 views

Terminate every background process

I have a few Stopped background processes. kill $(jobs -p) and kill `jobs -p` have no effect kill %1, kill %2, etc. successfully terminate individual processes How can I kill every background ...
7
votes
5answers
311 views

How to extract logs between two time stamps

I want to extract all logs between two timestamps. Some lines may not have the timestamp, but I want those lines also. In short, I want every line that falls under two time stamps. My log structure ...
1
vote
0answers
14 views

sticky alias command [duplicate]

I want to have the alias inst to be used instead of installpkg /tmp/ and then install packages by inst <pkg name>. But in normal alias define, We can not stick alias name to the package name and ...
1
vote
1answer
22 views

How do I display a manpage with groff in/on msysgit?

I've been unable to correctly set up a MANPATH environment variable in msysgit (1.9.0; 20140217) on Windows 7 (which is not my main concern here). Every time I execute the man command, I recieve the ...
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 ...
1
vote
1answer
60 views

How to check for a folder inside a particular folder in shell script?

I am working on a shell script and python script as well. Python script is passing certain parameters to my shell script and then I am using those parameters in my shell script. Below is my shell ...
1
vote
2answers
204 views

Using sudoers to allow php to run command

I am trying to get my php page to run this command: shell_exec("sudo /home/xbian/433Utils/RPi_utils/codesend {$num}"); So I added this entry to my sudoers file with visudo: www-data ALL=NOPASSWD: ...
2
votes
1answer
30 views

Conditionals for fish shell

I am going through the fish shell tutorial and find that this simple if-else block does not work if grep fish /etc/shells echo Found fish else if grep bash /etc/shells echo ...
5
votes
2answers
198 views

Get the actions for a command programmatically

Let's take the git example: $ git<TAB><TAB> git git-import-dscs git-shell git-buildpackage git-import-orig git-upload-archive git-dch git-pbuilder ...
22
votes
4answers
26k views

How to monitor CPU/memory usage of a single process?

I would like to monitor one process's memory / cpu usage in real time. Similar to top but targeted at only one process, preferably with a history graph of some sort.
3
votes
2answers
145 views

Shell script wait for background command

I am writing a script, but there is something I need that I can't find a way to do it... I need to make a command in background "command1 &" and then somewhere in the script I need to wait for it ...
1
vote
2answers
29 views

tar specific files based on a pattern

I got a lot of files with the following format: 2014_04_01_11.txt 2014_04_01_12.txt 2014_04_01_13.txt 2013_03_25_12.txt 2013_04_29_15.txt I would like to tar all theses files into an archive 20?? _ ...
73
votes
3answers
7k views

Why is “echo” so much faster than “touch”?

I'm trying to update the timestamp to the current time on all of the xml files in my directory (recursively). I'm using Mac OSX 10.8.5. On about 300,000 files, the following echo command takes 10 ...
1
vote
1answer
30 views

`tar` with `find` with removing original file extension

I want to create tb2 files from bunch of text files like this. tar cfj $(basename ./2014_04_09.txt .txt).tb2 $(basename ./2014_04_09.txt) With this command I can create a archive file 2014_04_09.tb2 ...
3
votes
5answers
1k views

Formatting the output: Underlining

I wrote the following function in ksh that prints its first argument to the screen and underlines it with the appropriate ammount of - character: print_underlined () { word=$1 echo $word ...
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# ...
3
votes
1answer
27 views

Merging text files based on their filename

I have hundred of files with the following format: 2013_01_19_xyxyxyx.txt 2013_01_19_xyxyxyx.txt 2014_03_21_xyxyxyx.txt 2014_03_21_zxzxzxz.txt 2014_03_22_abababa.txt 2014_03_22_cbcbcbc.txt etc. I ...
1
vote
0answers
16 views

Execute commands on TMUX Detach

Is it possible to execute commands on tmux detach? I usually have a rails console and server running in the tmux session, on detach is it possible to automatically end those? Thanks.
1
vote
1answer
471 views

Deleting Non-empty Directory with smbclient

How can I remove a non-empty directory with smbclient? I have tried the following: 1) rm Result: NT_STATUS_NO_SUCH_FILE listing [dir_path] 2) recurse;rm Result: No Error but also nothing ...
0
votes
3answers
367 views

Proper place to put shell prompt(PS1) when use sh/bash/zsh together

I'm using dash(sh) or bash or zsh. If possible, I would prefer to put in common place. I want to put proper PS1 settings when I interactive with shell, so these situation should be considered login ...
7
votes
5answers
472 views

copy smallest files first?

I have a large directory containing subdirectories and files that I wish to copy recursively. Is there any way to tell cp that it should perform the copy operation in order of file size, so that the ...
8
votes
3answers
523 views

/bin /etc /lib64 /root /sbin deleted or moved by mv folder/* /* while su

OS is Centos 6.5 64-bit I downloaded a tar file and wanted to untar and mv it. I untared, then accidentally (as root) ran mv folder/* /* instead of mv folder/* . bash said it couldn't overwrite some ...
2
votes
2answers
75 views

Close all file descriptors in bash

Is there a way to close all the open file descriptors, without having an explicit list of them beforehand?
2
votes
1answer
50 views

What is the ` character or symbol called and what is its significance outside of SE code formatting? [duplicate]

What is the ` character's name and what is its significance outside of SE code formatting because I cannot get it to work? I'm familiar with its use in the Stack Exchange forums used to format code ...
3
votes
1answer
125 views

Why is my find not recursive?

I am running the following command, but it is not performed recursively: find . -name *.java I know there are java files further down in the current directory but it is performing the find on the ...
2
votes
4answers
70 views

Can a running script identify the logging context?

Let us say I redirect the STDOUT, STDERR of a program to files. ./script.sh 1> output.log 2> error.log Can the running program find this out i.e. know the paths to these files?