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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3
votes
2answers
78 views

What is the format for piping a message into sendmail?

I am using the following command to create messages on the fly, and send them: echo "Subject:Hello \n\n I would like to buy a hamburger\n" | sendmail email@example.com It seems that when you send ...
1
vote
1answer
31 views

Using double or no quotes with wildcards

I came across this article which attempts to explain the find command.It gives an example of find /tmp -iname "data*.txt" now this article here states that Double quotes do not suppress the ...
3
votes
2answers
83 views

Execute code on remote machine and copy the results back

I'm using some old Fortran code that uses some peculiar memory handling. To make the long story short, it runs on my local machine but fails on the remote one. This is why I would like to ssh to my ...
2
votes
3answers
3k views

sed - how to replace a single quote?

This works fine: sed -i 's# @driver.find_element(:xpath, "//a\[contains(@href,##' temp_spec.rb against a source of @driver.find_element(:xpath, "//a[contains(@href,'change_district')]").click ...
1
vote
3answers
96 views

What return/exit values can I use in bash functions/scripts?

I want to know what return values we can use that will not be mistaken by for ex. SIGINT? ex.: $sleep 10 $#hit ctrl+c $echo $? 130 so I know I must not use anything like return 130 or exit 130 so ...
6
votes
3answers
475 views

How do I print '-e' with echo?

I know that echo -e is not an ordinary command. I have tried echo '-e' and echo \-e but they still don`t work.
1
vote
3answers
502 views

Different “history” command output after reconnecting via SSH

Why do I get different results for the "history" command for the same user after I reconnect a disconnected SSH session? I connect to a server using putty (SSH), say as root My network gets ...
1
vote
3answers
52 views

How to remove matching files from directory A in directory B in the command line?

I have some duplicate files in directories A and B, how could I delete the dupes in B using the filenames from A in bash? How to do it in other shell's is a welcome bonus.
1
vote
1answer
25 views

RYSNC over SSH not working for restricted shell

I need to give access to some Mr X in my production server so that he can push files to my server. Since there is no necessity to give him shell access , I decided to use restricted shell (rssh) so ...
1
vote
1answer
26 views

How do I get a list of the values of matching attributes using xmllint and xpath?

I'm trying to use xmllint to parse names of Solr cores from the configuration file. This works: xmllint --xpath /solr/cores/core/@name solr.xml |grep -Po '(?<=name=")[a-z-]+(?=")' And it returns ...
2
votes
1answer
45 views

Help with using quotes in grep searches

I have a file with variables in it of the form a(i)%b(j)%c where the a, b, and c are always the same, but the indices i and j may be different (including multiple characters). So I've played around ...
2
votes
1answer
57 views

GDB cannot exec my test program

My computer run with Ubuntu 14.04. GDB seems to be abnormal in different account. For example I make a very simple test. I write a file under ~/test/test.c like this: #include <stdio.h> ...
0
votes
2answers
62 views

Bash getting integer expression expected

I have following script to check disk usage #!/bin/bash # set alert level 90% is default ALERT=10 OIFS=$IFS IFS=',' storage=$(df -H | grep -vE '^Filesystem|tmpfs|cdrom' | awk '{ print $5 " " ...
2
votes
2answers
38 views

Adding “ubuntu” user to Vagrant ubuntu instance

I am using a vagrant box : uname -a Linux precise64 3.2.0-23-generic #36-Ubuntu SMP Tue Apr 10 20:39:51 UTC 2012 x86_64 x86_64 It does not have ubuntu user setup , instead it has vagrant one ,so I ...
0
votes
4answers
45 views

Print only directories with more than 31 files

I am using this script to count files on my directory and sub-directories: for i in $(find . -type d) ; do printf "$i %s\t" ; ( find $i -type f | wc -l ) ; done This script works fine. What I ...
4
votes
1answer
91 views

Executing a “fork bomb” safely

We've all seen the "fork bomb" that will render a host non-responsive, even if executed in an unprivileged shell: Warning: Do not execute the following shell script. Just don't. :(){ :|:& };: ...
2
votes
2answers
43 views

Tar a list of files which don't all exist

I'm running a command from a script like tar -c -f ar.tar a b c d where b, c, and d may not exist, and may be directories. The solutions that I've come up with are piping the output of ls -d to ...
3
votes
4answers
203 views

what is the difference between `find .` and /home/user/* as an input to for command

What is the difference between find . and /home/user/* as an input to for command.? For example: for var in $(find .) do echo "$var" done or for var in /home/user/* do echo "$var" done In the ...
1
vote
1answer
39 views

How portable is this shell assignment?

VAR=${VAR:-value} The purpose is to set the environment variable VAR to value unless it's already set. I see it works in bash and dash, but how portable is it?
20
votes
4answers
51k views

How to add repository from shell in Debian?

In Ubuntu one can add a repository to apt-get via the following command - sudo add-apt-repository ppa:yannubuntu/boot-repair As Ubuntu is based on Debian code base, I was expecting that the same ...
2
votes
2answers
83 views

Typing text from a shell script [duplicate]

I'm new to shell scripting. I'd like to know if there's a command similar to "echo" for displaying text in a terminal, but instead of simply displaying it immediately, it actually types it, like if ...
2
votes
1answer
27 views

Append same timestamp to multiple filenames

I have several files that I ftp each hour. The receiving system needs to have some sort of identifier that they came from the same batch, so I would like to append a timestamp to the filename. That ...
1
vote
1answer
118 views

Adding multiple user with shell script on Ubuntu

Can someone help me in providing me the shell script for creating multiple users on Ubuntu. Password needs to be different for each user. Thanks in advance
0
votes
0answers
265 views

python error using an executable with Z shell

I'm getting this error from the Unix Z shell (I'm on Mac): python: posix_spawn: /System/Library/Frameworks/Python.framework/Versions/2.6/Resources/Python.app/Contents/MacOS/Python: No such file or ...
5
votes
3answers
284 views

How to view last 5 lines from last created/modified file?

Every day I have to take backup and update the status to support teams at particular time for which I need to check last 5 lines of last created/modified *.aff file in a directory and update them. ...
0
votes
1answer
16 views

Loop across url with static tokens with Oauth

I need to write a loop where I need to pass a "token" (which is fixed) and a variable (i) in the url. Is there any way I can achieve that? I wrote the following code but it is not working. If I put ...
1
vote
1answer
986 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 ...
9
votes
3answers
9k views

Understanding backtick (`)

I am trying out the command $ b=5; echo `$b`; -bash: 5: command not found but it does not print 5 as it is supposed to. What am I missing here? What does ` (backquote/backtick) mean in bash? seems ...
2
votes
2answers
45 views

for loop to iterate through some file nth position

How do I iterate for nth file in a for loop in unix? below some code I have tried but not succeeded #!/bin/bash # n=2 array=( "CTL_MLPOSDTLP1_1.ctl" "CTL_MLPOSDTLP1_2.ctl" "CTL_MLPOSDTLP1_3.ctl" ) ...
2
votes
3answers
33 views

how to run the dialog command with proccess

Please look on my code – ( bash script ) I want to display both dialogs on the screen on the same time, one dialog display the: tail –f from - /var/log/proccess1.log , and the second dialog ...
1
vote
4answers
117 views

How to subtract two times in shell

I nee to subtract two lines which is in the format of time in shell. Th time format is hh:mm:ss I used the code below to get the time. cat /var/log/kern.log |grep usb |tail -2| awk '{print $3}' The ...
0
votes
2answers
41 views

How can I redirect the same message to both stdoud and stderr (without temporary object)

It is easy to redirect stdout or stderr to the same output (file or one of the 2 std output) with a 1>&1,>&2 and/or >file. Is there a way to send the same output to both the std ...
0
votes
1answer
33 views

Check for subdirectory

A)I used the following code to get the modified date of a file. But this is also selecting the subdirectories and thus returning an error. How van I fix this. for file in $1/*; do echo `stat ...
2
votes
2answers
92 views

How to show only total file size of particular extension by `du` command

I have a hundreds of pdf files and html files in a directory. And I want to know total size of pdf files. By command du -ch /var/foo I can see total file size but I only need last line, the total ...
28
votes
5answers
3k views

Does /usr/sbin/nologin as a login shell serve a security purpose?

In my /etc/passwd file, I can see that the www-data user used by Apache, as well as all sorts of system users, have either /usr/sbin/nologin or /bin/false as their login shell. For example, here is a ...
77
votes
8answers
10k views

Why *not* parse `ls`?

I consistently see answers quoting this link stating definitively "Don't parse ls!" This bothers me for a couple of reasons: It seems the information in that link has been accepted wholesale with ...
0
votes
1answer
28 views

elif command is throwing error [closed]

Hi is the below elif command correct? elif [[ "${FILECOMMAND}" = "" ] && [[ -f ${ZIPFILE} ]||[ -f ${ZIPFILE3} ]]] I am getting an error when I run it.
0
votes
1answer
25 views

Pre-process 1 single option

I've got a Shell script (intended for Linux/Mac/Cygwin users) that wraps an executable JAR. Before passing the arguments (long or short form) to the Java program, I need to pre-process one single ...
2
votes
1answer
119 views

Writing to an interactive prompt

I’m using the ftp command line tool and want combine scripted input with user input. With only user input the prompt looks like this: ftp> But when I try to insert some input with a script, like ...
1
vote
2answers
43 views

Shell, howto extract letters from $line1=“Test this… test this!”, and print one by one

I am writing a script, which I would like to spice up a bit. What I need, is a loop, which takes one letter at a time, including space, and then write it on the screen, like an old typewriter would ...
2
votes
1answer
49 views

PS1 prompt showing different on local and remote console

This is my PS1 prompt: export PS1="\[\e]0;\u@\h: \w\a\]${debian_chroot:+($debian_chroot)}\[\033[01;35m\]\u@\h\[\033[00m\]:\[\033[01;34m\]\w\[\033[00m\]\$ " That shows perfect in remote (SSH) ...
3
votes
2answers
64 views

Syntax error: word unexpected on io redirection on file descriptor ≥10

I have the following shell script on debian 7: #!/bin/sh case "$IFACE" in lo) # The loopback interface does not count. # only run when some other interface comes up exit ...
0
votes
1answer
31 views

Trying to make aliases that open the last modified file

One thing that I frequently do is edit the most recently modified files, so instead of typing "ls -lr" and then "vim lastfile", I thought I would make some shortcuts in my ~/.bash_profile file: alias ...
0
votes
1answer
44 views

Why can't my `date` deal with timezones? [duplicate]

I'm having some weird issues with GNU coreutils date v8.4 (CentOS) that aren't occurring in v8.21 (Ubuntu/Mint). On v8.4, I get the following output (I'm in PST): $ date --version | head -n 1 date ...
6
votes
2answers
933 views

How can I forward a already forwarded ssh key into tmux?

I'm connecting through SSH from a machine where my keys are stored, forwarding to a second machine, and then try to use the keys from within tmux. I appear to "loose" the forwarding when entering ...
2
votes
5answers
109 views

How to find different files in UNIX based on . extension?

How to find different files in UNIX based extension. Lets say suppose if I have 100 files for each vamsi.log-vamsi100.log, krishna.txt-krishna100.txt, super.csv..., rajat.jpeg..., ...
0
votes
0answers
19 views

How to check if a shell is interactive or not for Bourne shell [duplicate]

How can I test with a command/condition if I am in an interactive (ran by user) or a batch (ran by a cron job) Bourne shell (not Bash)?
0
votes
2answers
39 views

can I use logical operators to remove all files that matches with one and/or other pattern in a single line?

I want to remove .txt or .csv files in a single line. What I have in my directory tachomi$ ls file1.csv file1.sql file1.txt file2.csv file2.sql file2.txt I only want .sql files so I want to ...
1
vote
1answer
35 views

For loop for curling on multiple pages with API's

I am trying to crawl a website for fetching pages using an API. When I issue the command cd desktop/mysite ; curl -O https://api.mysite.com/info?page=2 I get the data on the desktop. Then I wanted ...
3
votes
1answer
22 views

I need to create file with name is the result of the command in Solaris

I need to create only one file with name is the result of the command ls -l | head -2. I can't use environment variables. The filename must contain newline symbols. I've tried to use touch 'ls -l | ...