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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0
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1answer
63 views

script to compare two string “foo” and “bar”

I'm going to create a script that should print "foo" or "bar" when a user's input is "foo" then print "bar" or when the user's input is "bar" then print "foo", otherwise show "invalid string". Here's ...
2
votes
2answers
109 views

how to parse a file that is changed continuously using awk?

for example if we have a file contains : Hello world Hello earth Hi everybody we can easily parse it to get the first and second columns of the lines contains the word Hello using awk: awk ...
1
vote
1answer
41 views

Remove BS and ESC from Log files

Whenever I use the script command to record the keys I type or when I activate the logging mode in screen, all BS (Backspace) and ESC (Escape) key presses are also included in the file. e.g: cd ...
5
votes
2answers
124 views

How exactly does `if $cmd ; then $cmd ; fi` differ from `$cmd && $cmd`?

In an answer to another very good question I made the following assertion: According to my reading of the POSIX specs, the use of one or the other makes no difference from a parsing standpoint. ...
8
votes
4answers
806 views

Bash syntax error when “else” follows an empty “then” clause

Why would following script not execute, but give a syntax error of else: LOGS3_DIR=~/logs if [ -d "$LOGS3_DIR" ]; then cd cd "$LOGS3_DIR" echo "$LOGS3_DIR" for filename in `find "." -mtime 1 ...
3
votes
2answers
151 views

How do I echo an expression with both single and double quotes?

I have tried many things, but I'm new to the shell. Is it possible to have both double and single quotes within an echo? I want to generate echo "scan 'LPV',{FILTER => "(PrefixFilter ...
0
votes
0answers
16 views

convert many eps files in single page pdf or ps file using shell script [duplicate]

I have many eps files and convert them into one page pdf or ps files.
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0answers
27 views

convert many eps files in a single pdf or ps file using shell scriptI

I have SSt12.OLR.1.eps, SSt12.OLR.2.eps SSt12.OLR.3.eps SSt12.OLR.4.eps ......and covert these eps files into single pdf or post script file. please suggest a shell script.
3
votes
2answers
124 views

How to send an alert if the DHCP range exceeds using shell script?

I've install and configure DHCP server on CentOS 6.5. I've also added a subnet to the dhcpd.conf file as follows: subnet 192.168.1.0 netmask 255.255.255.0 { option domain-name-servers 192.168.1.2, ...
0
votes
2answers
40 views

How to create a variable $ldir at your home directory that contains the relative path to letters?

If there's a directory on your Desktop called letters: 1) How to create a variable $ldir at your home directory that contains the relative path to letters? 2) How to copy a text file f1.txt to the ...
11
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13answers
2k views

How to read an IP address backwards?

If we have this string (IP address): 192.168.1.1 How can I derive the (DNS reverse record form) from this string, so it will be shown like 1.1.168.192.in-addr.arpa using a shell script?
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votes
2answers
111 views

Shell Script to capture file name and file size in CSV format [closed]

I have number of zip files in a certain folder. I want to capture file name and the size of the file in a csv format containing file names and sizes, one file per day. The file names do contain the ...
1
vote
2answers
103 views

Changing user to root when connected to a linux server and copying files

My script is coded in a way that doesn't allow you to connect to a server directly by root. This code basically copies files a server to my computer and it works but I don't have access to many files ...
3
votes
3answers
278 views

Case-insensitive substring search in a shell script [closed]

I'm trying to create a script which runs a command and compares the output of that command to a certain string to see if it contains that substring, ignoring the case of the string needed to be ...
2
votes
3answers
106 views

grep on a Java Method

Lets say I have a java class called DirectAction some of the methods in the class have the word "action" or "Action" What is the grep command to get the names of all the methods who have "Action" or ...
5
votes
3answers
991 views

Prompt user to login as root when running a shell script

The problem I am getting is, when I enter the command, su - root at the beginning of my shell script file, it prompts the user to enter the password and then does NOT continue with the rest of the ...
5
votes
2answers
136 views

What does ${3#?} do?

I have a script with the following variable assignment: TEST_VARIABLE=${3#?} What does the ${3#?} do?
2
votes
0answers
157 views

How does SELinux / SEAndroid prevent or allow pseudo terminal allocation?

I'm trying to resolve an SSH connection issue on an Android phone running SELinux in "Enforcing" mode. The problem is that any SSH connection that tries to allocate a pseudo-terminal (/dev/pts etc) is ...
1
vote
2answers
113 views

Run jar on startup in all *nix based systems

I have a jar file which I need to run at startup in all distros of Linux. My previous question here, gave me an idea a rough idea on X-servers. Since I wasn't able to perform startup, I moved on to ...
1
vote
2answers
55 views

Temporarily freeze a process upon shell interaction

Let's say on a single console I have tail -F running, showing the output of many log files in realtime. Sometimes I need to run commands there too, however, and examine their output briefly, without ...
1
vote
2answers
100 views

Difference between command `ls 2 >tmp >tmp` and command `ls > tmp`

I am relatively new to Linux systems. I don't understand what is the difference b/w ls 2>tmp >tmp and ls > tmp. They both seem to do essentially the same thing, creating a file tmp and ...
1
vote
1answer
33 views

bash completion on posix mode

I would like to use an interactive posix bash shell but the autocompletion feature doesn't work. When i type the tab character it simply prints a tab. The tab completion only works when i'm on a non ...
0
votes
1answer
36 views

bash completion on posix mode [duplicate]

I would like to use an interactive posix bash shell but the autocompletion feature doesn't work. When i type the tab character it simply prints a tab. The tab completion only works when i'm on a non ...
1
vote
4answers
107 views

How to set the process won't be terminated when the terminal stops

[Edit] Make it simple. I invoked java xxx... on Machine A using putty to connect from Machine B. However I cannot reach Machine B. How can I connect Machine A from Machine C to set the running ...
0
votes
1answer
73 views

Linux script for printing name [closed]

I have to Prompt the user to enter his/her name and Print all combinations of three letters from the name. How to write script for this?
2
votes
1answer
88 views

How to create an executable bash script for these commands?

I wish to create an executable bash script that will run the following commands as root, that is, using sudo su iptables-save | awk '/^[*]/ { print $1 } /^:[A-Z]+ [^-]/ { print ...
1
vote
1answer
61 views

Prevent active file removal on an NFS filesystem

I clear my logs using following script - find "." -mtime 1 -type f -print0 | xargs -0 rm -rf But it deletes the active files also and creates .nfs… files instead. Is there any way to prevent ...
3
votes
1answer
63 views

How to find all paths not compatible with Windows?

On most Linux filesystems, NUL (\0) is the only invalid character in paths (and / is reserved as the path separator). Windows has a complicated set of rules for valid paths. Rather than fixing paths ...
9
votes
2answers
232 views

Closing a file descriptor, >&- vs <&-

In the bash tutorial I am reading, it says that if you open a file descriptor for reading, i.e. exec 3< echolist Then you must close it like this, exec 3<&- However, if you open a file ...
1
vote
1answer
43 views

GeeXbox ls shows no date?

Recently, I tried connecting to my GeeXbox via WinSCP but got an error indicating the output of ls could not be parsed. Apparently, my ls does not include a time stamp! What might be the cause and ...
18
votes
2answers
658 views

Why does my shell script choke on whitespace or other special characters?

Or, an introductory guide to robust filename handling and other string passing in shell scripts. I wrote a shell script which works well most of the time. But it chokes on some inputs (e.g. on some ...
0
votes
1answer
26 views

better use of find - rvm.sh

I am trying to find rvm.sh as I am receiving the infamous rvm is not a function error. The file in most linuxes is supposed to be at /etc/profile.d/rvm.sh However on opensuse it is not there so I ...
3
votes
5answers
165 views

Listing directories based on size from largest to smallest on single line

I can use the following command to get a list of directories and their sizes and sort them from largest to smallest (in the example I renamed the directories to numbers to make this easier to ...
3
votes
2answers
106 views

Start zsh with a custom zshrc

I want to be able to start zsh with a custom rc file similar to the command: bash --rc-file /path/to/file If this is not possible, then is it possible to start zsh, run source /path/to/file, then ...
2
votes
2answers
133 views

Is there any CLI/terminal slideshow app?

I'm asking myself: is there, on linux, any software that can build and show simple slides on terminal, like the slides you make on Libreoffice Impress (but way more simple)? This would be a great ...
0
votes
0answers
47 views

how to pass asterisk as a parameter to getopts [duplicate]

I wrote a shell scripts with getopts to take arguments. But I want to pass an asterisk as an argument, for example script -a"Hello * all" -b"Another argument" if I echo the -a argument from the ...
2
votes
1answer
47 views

Capture symbolic link into Unix/Linux variables

Say I have a folder with a series of symbolic links: ussdv103:en195d; default$ pwd /oradba/app/oracle/admin/database1 ussdv103:en195d; default$ ls -ltr exp -> ...
1
vote
2answers
140 views

How to show specific lines from specific columns of a file

First off, I'm not allowed awk, sed or perl. For my assignment I was given a file of employee list: Marketing Ranjit Singh FULLEagles Dean Johnson Marketing Ken Whillans FULLEagles ...
1
vote
1answer
27 views

Using cat to modify ~/.bash_profile seems to remove __git_ps1 compeltely

I want my prompt to display the current git-branch when inside of a repo directory. e.g., [desktop repo(master)]$ In my terminal I can type: cat <<EOF >> ~/.bash_profile ...
0
votes
3answers
83 views

SSH Agent-Forwarding works, but what about sudo -u username no shell/ permissions? composer

Working on a remote server (A) I want to use my local SSH-Keys to access a repository on another server (B) that is not controlled by me. Generally this works like a charm. I log in as myUsername ...
4
votes
1answer
77 views

Blank lines when executing “grep | xargs” in a “find -exec”

I'm trying to list all directories of a web server that are blocked by Apache via a .htaccess (containing deny from all). I've managed to get the list of blocking .htaccess but when I try to extract ...
1
vote
1answer
46 views

Use a bash function in a pipelined command

I have a command similar to: ... | sort -u -V. Since some versions of sort do not support the -V flag, I thought it would be great if I made a function that conditionally adds the flag. But, it seems ...
1
vote
1answer
88 views

Is there a GUI debugger for shell scripts

Debugging bash scripts on command line is complicated. Is there a good GUI based debugger available for debugging bash scripts?
0
votes
1answer
37 views

egrep part required for svn hook script

I am trying to write a pre commit hook script to Enforcing tag naming convention like < application>_ < project >_ < version>_ < iteration> this using a shell script can anyone ...
0
votes
1answer
51 views

ksh, perform action when reaching loop maximal value

I am looking to write a small korn shell script doing 5 tests (by waiting some time before each one) and then, if they all fail, performing an action. I was looking at doing something like : for ...
0
votes
2answers
62 views

run shell scripts in a sequencing way?

I have 4 shell scripts and I want to run them in a sequencing way: script1 -> script2 -> script3 ->script4 in a local machine can I ensure this by make the scripts executable and creating a new ...
0
votes
1answer
33 views

how can I replace a record in my DB (mySql) by new record?

I have created a shell script to connect to a DB and INSERT IPs and MACs from dhcpd.log file: #/!bin/bash dhcpLogFile="/var/log/dhcpd.log" NumberOfLines=$(awk '/DHCPACK/ { print $8} ' $dhcpLogFile | ...
1
vote
2answers
47 views

Is it secure to connect remotly to Mysql using shell?

I have created a shell script to connect to a DB and do some queries: #/!bin/bash ... ... mysql -h remote -u root --password='pw' MatchingDB some SQL queries My question is : Is this connection ...
0
votes
1answer
227 views

Proper escaping of double quotations for curl post data?

I'm trying to test out a server, by sending it JSON data and reading the response. I need to POST data like {"item":"value with spaces"} but when I use curl I find that it sends the backslashes as ...
1
vote
4answers
182 views

renaming multiple files increment order

I have the following files SSt12.precip.374.sub.climatology.ctl SSt12.precip.2874.sub.climatology.ctl SSt12.precip.3764.sub.climatology.ctl SSt12.precip.6774.sub.climatology.ctl I want to rename ...