The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks. Use this tag for questions applying to /bin/sh and most compatible shells (ash, bash, ksh, zsh, …).

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5
votes
3answers
263 views

How to put a newline special character into a file using the echo command and redirection operator?

I would like to create a file by using the echo command and the redirection operator, the file should be made of a few lines. I tried to include a newline by "\n" inside the string: echo "first ...
0
votes
1answer
81 views

How to convert Ubuntu init script to Amazon Linux AMI init script?

I had a Ubuntu based Amazon EC2 server where I was running my java based application. For this I had written a init script which was running perfectly and as follows #! /bin/sh # set the environment ...
0
votes
1answer
31 views

Exporting a piped command without evaluating output?

I'm trying to set an export that would effectively kill a process based on the PID that pgrep feeds it. Running the command kill $(pgrep myAppName) appears to work (if 'myAppName' were the name of an ...
2
votes
4answers
85 views

Add 0 in the middle of a filename

$ ls pro2e_u01_txt_vocabulaire_11_descriptiveadjectives.mp3 pro2e_u01_txt_vocabulaire_12_nationality.mp3 pro2e_u01_txt_vocabulaire_1_campus.mp3 pro2e_u01_txt_vocabulaire_2_personnes.mp3 ...
-2
votes
3answers
58 views

How to Show your main “shell” that you use.? in UNIX

How to Show your main “shell” that you use.? in UNIX is this command right ps -p$$ or if there is a different way? thank you
2
votes
1answer
38 views

Change Environment Path Variable Order

I am working on a CentOS box and trying to install a newer version of python. CentOS requires python 2.6.6 in order to run properly. To solve this I installed a second python (v 2.7.6) in ...
1
vote
0answers
25 views

get the apache document root using shell script [duplicate]

I am creating an RPM and in the pre stage, I want to determine apache's document root so I can copy the web application files there. First, I check if apache is installed. If apache is installed, the ...
2
votes
3answers
37 views

get the apache document root using shell script

I am creating an RPM and in the pre stage, I want to determine apache's document root so I can copy the web application files there. First, I check if apache is installed. If apache is installed, ...
4
votes
4answers
1k views

Why does `rm -f !(/var/www/wp)` leave files behind in /var/www?

Why does the rm -f !(/var/www/wp) command have no effect? I want to remove all the files in /var/www, except for the /var/www/wp directory, which should remain. root@born:~# ls /var/www ...
0
votes
3answers
40 views

Replacing line with its line number

How can I replace the whole line with no matching pattern just with the number of the line? sed -i "${line}p c\ "$PWD" " file.txt
0
votes
1answer
24 views

Rename and copy/move sets of similar named directories to another location

For a set of directories with similar names at different location, /foldX/dirA with sub-directories aa1 aa2 aa3 aa4 aa5 /foldZ/dirA with sub-directories aa1 aa2 aa3 /foldY/dirA with ...
-1
votes
0answers
41 views

What exactly is Ctrl + s? [duplicate]

In my terminal, if I press Ctrl+S it 'freezes' output, which can then be resumed with Ctrl+Q. What exactly happens here? What library/program supplies this functionality or at least says what ...
2
votes
4answers
132 views

How do I perform xargs grep on grep output that has spaces?

I'm searching for files based on a regular expression, and then I'm trying to search those files for content. So, for example, I have something like #Find all C++ files that match a certain pattern ...
28
votes
4answers
2k views

Why do many commands provide a “quiet” option?

Why do many commands provide the option -q or --quiet to suppress output when you can easily achieve the same thing by redirecting standard output to the null file?
1
vote
1answer
37 views

mv to file with

I ran the following mv command, apparently by mistake using backslashes by mistake instead of slashes. mv 2015-02-02_flyer_ppces.pdf ..\PPCES2015\2015-02-02_flyer_ppces.pdf The output is empty. ...
4
votes
2answers
220 views

BASH base conversion from decimal to hex

In Bash, how does one do base conversion from decimal to another base, especially hex. It seems easy to go the other way: $ echo $((16#55)) 85 With a web-search, I found a script that does the ...
1
vote
1answer
28 views

How to move directories based on the output of rhash (CRC32 check of .sfv) with bash/perl?

My idea, is to move the CRC-check OK folders (albums) into a lets say "complete+CRC_OK" folder with a script once per day in cron. I would need to put the rhash command in a loop with number of ...
5
votes
2answers
204 views

How to count duplicated last columns without removing them?

I have a file that contains 4 columns. I want to compare the last three columns and count how many times they occur without deleting any of the lines. I just want the count to be present in front of ...
13
votes
6answers
417 views

Extraction of .gz files contained in a folder

I have a folder containing approximately 320116 .pdb.gz files. I want to uncompress them all. If I use gunzip *.gz it gives me an error i.e. argument list too long. The folder is about 2GB. Please ...
0
votes
2answers
46 views

how to split the string after and before the space in shell script?

I am having a variable which shows on echo like this $ echo $var 129 148 I have to take only 129 as output. How will I split 129 and 148?
2
votes
2answers
131 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: ...
0
votes
1answer
42 views

introduce a c script in a bash file [closed]

My problem is to recover data keyed in text file in bash. I seek the command that can perform this task and I used sed, awk and even cut but I have not succeeded. One friend of mine suggested to ...
8
votes
2answers
225 views

How bash treats “> >()”

While experimenting with output redirection and process substitution I stumbled upon the following command and its resulting output: me@elem:~$ echo foo > >(cat); echo bar bar me@elem:~$ ...
0
votes
1answer
23 views

Why doesn't commons-daemon ./configure recognize $JAVA_HOME? [closed]

I'm trying to install a tomcat 7 server. I'm following these instructions from the tomcat 7 docs. I also set my JAVA_HOME variable in ~/bashrc as well as ~/.bash_profile and /etc/profile. I can do ...
1
vote
1answer
44 views

What is an alias really doing?

I'm looking for a way to check what an alias is really doing, without having to check the ${HOME}/.profile file, or whatever other file where you can define an alias. For example, if I run ll and I ...
2
votes
1answer
21 views

Making XMODIFIERS=@im=none emacs24 standard

I run emacs as XMODIFIERS=@im=none emacs24, otherwise some multi-keys for typing things like à won't work. How can I make this option permanent, so when I type emacs24, it runs as XMODIFIERS=@im=none ...
4
votes
4answers
136 views

Insert new lines with missing values (NA)

I would like to insert new lines in text files if there are missing values. I have for example the following text file (A.txt), for which line 5 is missing. In addition, as the file should have 12 ...
2
votes
1answer
126 views

Transform .csv into 3 columns and a row

Sample Input: id,Product1,Product2,Product3,Product4 1,0.1,0.3,0.8,0.7 2,0.6,0.7,0.5,0.9 I need output as : id,productname,product_val 1,Product1,0.1 1,Product2,0.3 1,Product3,0.8 1,Product4,0.7 ...
-4
votes
1answer
51 views

shell script for two numbers [closed]

Write a shell script to take two numbers from command line and show result of dividing small number with bigger number. Also note that it should not accept zero or negative number. If user enter ...
1
vote
0answers
46 views

How to move /usr folder and replace it with saved copy [duplicate]

If I made a backup of /usr with: # cp -r /usr /usrRESERVE1 how can i switch it back after some time: 1# mv usr usrRESERVE2 2# mv usrRESERVE1 usr second command will not work because mv is inside ...
1
vote
1answer
53 views

Ctrl+C process termination without Terminal killing

I started using Sublime Text 3 to compile my FreeFem scripts (interpretator PDEs package solver) under Ubuntu 14.04. To invoke the interpretator I customized the build system as follows "shell_cmd": ...
3
votes
2answers
70 views

save the number of files only in a specific folder

I'm using this script to save the number of files in a main folder, but it also counts the subfolders inside that main folder. nfiles=$(ls -1 /home/userA/mainfolder | wc -l) Any advice how I can ...
-2
votes
1answer
38 views

Append the content of a file to the value of a variable in ksh

Can we append the content of a file to the value of a variable in the Korn shell? How? /bin/ksh: $ B.11.31 Oct 1 2008 01:54:10 $ Version 11/16/88 blok.c $Date: 2008/08/20 12:15:51 $Revision: ...
0
votes
0answers
37 views

Linux . Kali on android 4.2.2

hope this topic finds you well E: Unable to Locate Package thats the error that occur when i try to install any tool in kali on android I'm using Android with version 4.2.2 and kali is working well ...
3
votes
2answers
135 views

How do you stop a bash shell expansion?

I know some methods for stopping process. When I type: echo {1..999999} > filename.txt I can't stop it from running. I can stop other processes with Ctrl+C | Ctrl+D | Ctrl+\ and etc. But none ...
1
vote
2answers
40 views

Need special validation for shell script

I want to create a bash script which will have lot of options while executing. # script.sh --dry-run --user <parameter1> --pass <parameter2> I heard about getopt option but looks like ...
0
votes
2answers
31 views

Why is wget still failing even after enclosing the URL with double quotes?

I enclose URLs I want to wget with "" since most of them have spaces, braces, etc. It usually works fine, but I can't get this URL to work: wget "http://xxxx/Sankarea - 6 - It`s Because I... Ran ...
1
vote
2answers
54 views

sh -c: Unterminated quoted string error [duplicate]

I've spent hours trying to understand the following error. My Script CMD="sh -c 'echo \"a\"'" $CMD Error: "a"': 1: "a"': Syntax error: Unterminated quoted string of course when I do echo $CMD ...
1
vote
2answers
276 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: ...
1
vote
1answer
38 views

Saving colored output regardless of the source

How can I save colored output to a file regardless of the source when the sources turn coloring off if they detect their stdout isn't a terminal?
-1
votes
1answer
28 views

Remove line breaks in a FASTA file

I have a fasta file where the sequences are broken up with newlines. I'd like to remove the newlines. Here's an example of my file: >accession1 ATGGCCCATG GGATCCTAGC >accession2 GATATCCATG ...
2
votes
2answers
162 views

How does one append a unix timestamp on a filename which is inside an argument?

To be more specific, I want the Unix timestamp to be appended to my file name: db:backup --database=mysql --destination=s3 --destinationPath=date+random.sql --compression=gzip However, this gives ...
-1
votes
2answers
67 views

Difference between 'echo' and 'echo -e' [closed]

What is the difference between echo and echo -e? Which quotes should be used to execute a command after echo ie: echo "..." or echo '...'? Also what functions are available for the command echo?
-2
votes
1answer
63 views

How to parse json output through shell / Python [closed]

I am running a curl command which gives me json response. Now I want to parse the response output to get the keys and corresponding values from the output or getting value for a particular key. I ...
0
votes
0answers
35 views

How can I disable FTP access/login for users

I want to temporarily disable the FTP Access of the FTP users I have tried following commands for user "aadmi" but still able to login sudo passwd -l aadmi which said Locking password for user ...
3
votes
3answers
123 views

Understanding Bash's Command Substitution

I am trying to understand how exactly Bash treats the following line: $(< $FILE) According to the Bash man page, this is equivalent to: $(cat $FILE) and I can follow the line of reasoning for ...
1
vote
1answer
35 views

Not getting the desired output for echo command [duplicate]

Below is my script. #!/bin/bash SERVERS="sl20rht00-t" #SERVERS="shcbrht01-t" USR="adm-dt-c" for host in $SERVERS do ssh -tt $USR@$host 'sudo cp /etc/sudoers /Backups/sudoers_11thmarch2015; sudo cp ...
1
vote
1answer
286 views

permission issues while doing ssh setup in cygwin

I'm trying to setup ssh-host in cygwin. Getting the below error: *** Warning: The permissions on the directory /var are not correct. *** Warning: They must match the regexp d..x..x..[xt] *** ERROR: ...
3
votes
2answers
146 views

Meaning of `cat /dev/null > file`

In a document created by a former coworker there is this command: cat /dev/null > /var/spool/mail/root It says next to it that it will clean out mailbox. Can someone please explain how/why ...
-2
votes
2answers
34 views

grep to get all the getters from a java file

I have a java file called Friends.java . There are 5 variables and each variable has its own getter. Assume that all the functions below follow standard java standard, i.e public methodName(){ //Some ...