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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1answer
67 views

How do I put a time stamp with: wget --output-file=[FILENAME] [URL]

So I've been trying to put a timestamp on some images I'm downloading from a webcam, but so far it's been saving the images with the names camera3_date' here's my line that I enter: wget ...
0
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1answer
47 views

check status process output

I wanted to understand how to create a script sh that allows me to see if an additional script functions correctly. For now this is the script that I created. if /run.sh status echo "$SERVICEXE ...
2
votes
3answers
2k views

cshrc execute bashrc within itself?

My school has our Linux accounts using csh/tcsh by default. I, however, have a lot setup on my home bashrc and I'd like to use that at school. BUT there's also some important stuff that happens in our ...
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1answer
34 views

Trying to debug /etc/init.d/named, no output, replace > /dev/null with /var/log/named.log?

I'm trying to debug named, when I try: [root@test master]# service named start Starting named: [FAILED] it fails silently, so I tried: sed -i ...
15
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3answers
6k views

Bash: double equals vs -eq

I am doing integer comparison in bash (trying to see if the user is running as root), and I found two different ways of doing it: Double equals: if [ $UID == 0 ] then fi -eq if [ $UID -eq 0 ] ...
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2answers
101 views

How to read from a named pipe after the writer process exits?

I want to use named pipes as asynchrnonous task queues (JMS-like, perhaps). For example, suppose a client sends some data that I wish to insert into a database, but I want the client to disconnect ...
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2answers
2k 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?
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4answers
306 views

How to use sed to selectively remove leading zeros

How can I substitute/remove 0's in this, using sed: 2001:0db8:03cd:0000:0000:ef45:0006:0123 to make it looks like this: 2001:db8:3cd:::ef45:6:123 There are 8 pieces of 4's divided by : in the ...
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3answers
3k views

Removing a directory from PATH

I'm trying to compile wxWidgets using MingW, and I have cygwin in my path, which seems to conflict. So I would like to remove /d/Programme/cygwin/bin from the PATH variable and I wonder if there is ...
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2answers
11k views

How to print only the duplicate values from a text file?

Suppose there is a column of numeric values like following: File1: 1 2 3 3 3 4 4 4 5 6 I want the output: 3 4 That is, only the repeated lines. Is there any command line tools to find this ...
2
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3answers
71 views

Using a command's output to determine the name of the file to redirect output to

I want to run smartctl -a, and use the device serial number from that output as the name of the file to store the output in. I know this can be done by invoking smartctl twice, and slicing up the ...
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2answers
122 views

single quote within double quotes and the bash reference manual

In section 3.1.2.3 titled Double Quotes, the bash manual says: Enclosing characters in double quotes (‘"’) preserves the literal value of all characters within the quotes, with the exception ...
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2answers
840 views

How can variables use “~” for cd'ing?

How can I use a variable - $BASE in my cd. I tried the following but I get an error $ cd ~/z/repo_1_ruby_193/ 23:23:57 durrantm Castle2012 /home/durrantm/z/repo_1_ruby_193 $ BASE="~/z" 23:24:03 ...
2
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2answers
114 views

How can I test for a file having a value?

I am using source ~/.rvm/scripts/rvm repos="repo_1_ruby_193 repo_2_ruby_211 repo_3_ruby_191" > rvm_check.txt for repo in $repos do cd ~/zipcar/$repo 2>rvm_check.txt cd .. echo $repo if ...
1
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2answers
212 views

how to shutdown another computers by using their IPs in shell script [closed]

command to shutdown to collection of servers by IP in specific time by shell script "using ssh command"
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3answers
85 views

0 byte file created in a simple script

I have a script as below: #!/bin/bash df -k | tr -s " " "," | awk 'BEGIN {FS=","} {print $1,$5}'|sed 1d > file1.txt while read partition percentUsed do if [ $percentUsed > 75 ] then echo ...
1
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1answer
43 views

How do you make case statements with ranges

I'm supposed to: Make a case statement that will display the a grade after input. With no loop or conditional. A=90-100, B=80-89, C=70-79, D=60-69, F=0-59 This is what I have so far: ...
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3answers
177 views

How to create multiple files with different names and different extensions?

I'm trying to create some files that has different names and with different extensions. Let say I want to create for example 3 files with following name and extension: File001.000 File002.001 ...
1
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1answer
27 views

Root shell sees pip but sudo pip “command not found”

I have installed python 2.7.8 via make and make install and then pip via get-pip. I have to note that I work behind a proxy which I have set up via http_proxy ftp_proxy https_proxy in my user's ...
2
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6answers
10k views

Extract date from a variable in a different format

Let me explain you the problem $ date +%c -d "$d" Tue 31 Dec 2013 01:13:06 PM CET $ date +'Today is %F' -d "$d" Today is 2013-12-31 This solution corresponds to current date. But I have one ...
2
votes
3answers
257 views

Brackets in if condition: why am I getting syntax errors without whitespace?

I am using the below script to move two days back when script runs at starting two days of the year and also check first and second days of every month and move two days back. if [$month="01"] ...
2
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3answers
256 views

Bash File existence test is always true

I have the following lines of bash script to test whether a file exists: MYAPPPATH=$(find $APPDIR -iname myapp* -print) if [ -e $MYAPPPATH ] then echo "File exists" fi However when file ...
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4answers
5k views

symbolic link to a directory and relative path

I've created symlink with absolute path to the directory (Blink) and have for example following tree: $ ls -l /tmp/A total 0 lrwxrwxrwx 1 root root 6 Apr 3 12:27 Blink -> /tmp/B -rw-r--r-- 1 root ...
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6answers
1k views

How to clean up file extensions?

I have a directories with .MP3 files which I'd like to change the extensions to .mp3. What's the easiest way to do this? I'm think something along the lines of: find /RootPath -type f -iname "*.mp3" ...
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0answers
14 views

od: Put offset n to n of a hexdump to a file in proper hexdump -C (hex+ASCII) format

I have a 155GB canonical hex+ASCII hexdump hexdump -C blah > dump.dp Then ran: strings dump.dp | grep -bo 'XXXX' > found.txt So now, that file contains the string's hex offset in the ...
2
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2answers
48 views

Efficiently copy names in shell

I have noticed an efficient technique that some users use to quickly copy directory and file names in the terminal or shell. The behavior/usage is as follows: Issue ls Click on the desired entry, ...
5
votes
3answers
280 views

How to iterate a zero padded integer in bash?

How does one iterate a string with the form "[A-Z][0-9]*" Or for example: "A000001"? After receiving the variable I split: current_=$(mysql -h"$mysqlhost" -u"$mysqluser" -p"$PASS" "$DBNAME" -se ...
3
votes
1answer
53 views

Run vsim from dmenu — it only works when directly invoked in the terminal

Works: vsim, sh -c vsim Doesn't work: echo "vsim" | sh, echo "vsim" | xargs -I {} sh -c "{}" I want to run ModelSim (vsim) with dmenu, which is triggered using xbindkeys. Details vsim is a ...
1
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1answer
2k views

Cant ssh, connection terminates immediately with exit status 254

The most recent thing I remember is changing the soft and hard memlock ulimit to unlimited. Now I cant ssh into the machine. This is the ssh log. Authenticated to IP ([IP]:22). debug1: channel 0: ...
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1answer
88 views

Sh Script using ftp to put a list of files

So my Script looks something like this: #... files="$(find $line/processed/* 2>/dev/null)" #2>/dev/null used for error output suppression if [[ ! -z "$files" ]] then ...
2
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4answers
76 views

unix test when to use eq vs = vs == in test commands?

When should I use -eq vs = vs == e.g. [[ $num -eq 0 ]] [[ $num = 'zzz' ]] I've observed a pattern of using -eq (and -ne, etc.) for numbers and = for strings. Is there a reason for this and ...
61
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12answers
22k views

Get exit status of process that's piped to another

I have two processes foo and bar, connected with a pipe: $ foo | bar bar always exits 0; I'm interested in the exit code of foo. Is there any way to get at it?
1
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1answer
188 views

How to get owner and full path of 50 large size file across all users?

Below command list top 50 files regardless of subfolders. $ls -lR /root/home | sort +4 -5nr | head -50 Current Result: -rw-r--r-- 1 john dpst 192954384 Nov 7 07:36 filenxx1.gz ...
29
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7answers
2k views

Is test or [ or [[ more portable both between bash shells and between other shells?

I see I can do $ [ -w /home/durrantm ] && echo "writable" writable or $ test -w /home/durrantm && echo "writable" writable or $ [[ -w /home/durrantm ]] && echo ...
6
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4answers
588 views

How to cd automatically after git clone?

I want to automatically cd to the directory created by the clone command after I git cloned something. That is, without writing anything additional just git clone $url that the shell will somehow ...
1
vote
1answer
81 views

How to export string about France to Microsoft excel file?

One string file Str.rc about French language is here: ID_STR_BRIGHTNESS;,"Luminosité" ID_STR_CHILE_EASTER_ISLAND;,"Île de Pâques" ID_STR_CURRENT_CH;,"Saisie chaîne" ID_STR_DETAILS;,"Détails" ...... ...
3
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1answer
58 views

how to run multiple versions of one shell on a single machine

In order to test some scripts1 in as many environments as possible, I've set up several VMs with UNIX (or Unix-like operating systems): Linux Solaris OS X2 FreeBSD I assume, though, that in many ...
1
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2answers
48 views

Store stdout in variable and send command to background

I have a command in a bash script which I want to capture the output of and then send it to the background. How do I get this done? The following doesn't seem to work (it keeps blocking and outputs ...
1
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2answers
51 views

How to find number of Subdirectories under a given directory

In windows you get a count of the number of subdirectories within a directory.Is there any equivalent on Linux ? I'd like it to count recursively & Not stop at a single level.
1
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1answer
43 views

Make parent directories while creating a new file

I am aware of the fact that mkdir -p /path/to/new/directory will create a new directory, along with parent directory (if needed ). If I have to create a new file, along with it's parent directories ...
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votes
3answers
2k views

How to execute a bash script on multiple directories?

I have a conv.sh script that loops over MP3 files in the current directory and converts them into OGG. I have also several directories {F1, F2,..., F20} at /path/to/Files/. How should I execute ...
0
votes
1answer
30 views

How do I add text to an output file?

I have a script for doing whois lookups: #!/bin/bash for domain in `cat /Users/jason/Desktop/letters.txt `; do echo $domain >> /Users/jason/Desktop/whois-results.txt whois $domain | grep ...
5
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1answer
94 views

Shell one-liner for adding a line in the middle of a pipe

I write a script which sends the input file to CPP, then to grep, then to a certain program: cpp $1 | grep -v "#" | theprogram But, "theprogram" requires the input to start with a certain constant ...
22
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7answers
28k views

Execute a command once per line of piped input?

I want to run a java command once for every match of ls | grep pattern -. In this case, I think I could do find pattern -exec java MyProg '{}' \; but I'm curious about the general case - is there an ...
18
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5answers
5k views

echo a file without the first and last lines

Is there a simple way I can echo a file, skipping the first and last lines? I was looking at piping from head into tail, but for those it seems like I would have to know the total lines from the ...
2
votes
2answers
418 views

Want a seperate file to store mysql username, password, and database name

I have as script that dumps a mysql database, and compresses the file. What I want to do is have another (edit) file which can change the username, password and database name. Then somehow connecting ...
0
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2answers
46 views

Convert a float to the next integer up as opposed to the nearest?

The context is there are 2 variables that get divided to a floating point result like so: printf "%0.5f\n" $(echo 305/15 | bc -l) 20.33333 How can I always round up to the next integer i.e. 21? ...
2
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3answers
62 views

Remove files from listing that are created/modified on Saturday

I am not sure if it is possible. I do ls -l, it gives all the files in the current directory. Is there a way to say list only files that weren't created/modified on Saturday's with shell command?
2
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1answer
34 views

Problems with find, xargs and egrep

I this is what I what I'm trying to end up with (except working) find ./ -mindepth 1 -type f -mtime +60 -print0 | xargs -0 egrep -vZ 'vvv|iii' What am I doing wrong? $ ll total 0 -rw-rw-r-- 1 ...
0
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1answer
64 views

Command not found when run with sudo bash

I ssh into my machine and then, in order to run some commands, I need to sudo bash first. In an interactive terminal session, if I do this: [vagrant@33 ~]$ sudo bash [root@33 vagrant]# which bundle ...