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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2
votes
2answers
121 views

Can I change the shell used to run GUI applications from a Desktop Manager?

A bit of background I'm a developer and I install most of my tools in my home folder. So my shell's rc file is full of JAVA_HOME, GROOVY_HOME, MAVEN_HOME, ... variables. To expose all these ...
4
votes
2answers
6k views

Displaying the last N modified files?

How can I list the 10 most recently modified files of a certain extension, not all files, or the files modified during the last 2 days for example?
1
vote
2answers
19k views

Shell script to increment count of entries

I want a script which increments the count when the script runs. Basically I want to send an email notification when I find 10 devices down from the same country and scripts run after every down event....
2
votes
1answer
827 views

How to create a script, which runs another script in separate terminal window and does not wait?

I wrote the following #!/bin/bash cd ~/bin/red5-1.0.0 gnome-terminal --working-directory=. -x red5.sh red5.sh is the script to run (this is java written media server). My script above opens new ...
27
votes
2answers
8k views

How can I use column to delimit on tabs and not spaces?

I'd like to use Unix column to format some text. I have fields delimited by tabs, but within each field there are also spaces. column delimits on white space (tabs and spaces). How can I make column ...
-1
votes
1answer
143 views

Counters in shell

I am looking for a shell script where counter needs to be set for input paramter and do action once the count reaches to 5. The problem is there could be n number of input parameter and action should ...
12
votes
5answers
3k views

Why there are multiple shells in a Unix like system?

I have just started learning the fundamentals of Unix and wondering why there are so many shells in a unix like system . From the book Advanced programing in Unix Environment: A shell is a command-...
0
votes
1answer
1k views

Login script for bash not loading

I am very confused about the login script for bash. I have always used ~/.bash_profile to configure my bash shell. Now I am on a new system just as a user: I am not root. This system was originally ...
1
vote
3answers
540 views

I want to run commands like make, make install, python setup install without changing directories

I have written a script which will download software from the internet to the current user's home directory and then untar it. And then I have to make and make install it and in some software I have ...
10
votes
12answers
3k views

What's a good way to filter a text file to remove empty lines?

I have a .csv file (on a mac) that has a bunch of empty lines, e.g.: "1", "2", "lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum lorem ipsum ...
2
votes
2answers
857 views

How can I find matches with sed (or similar) for configuration parameters?

I'm pretty good at using php's preg_match (and similar) commands, and I'm also pretty good with regular expressions, but I don't do very well with sed. I have two shell scripts I'm working on and I'd ...
2
votes
1answer
3k views

Why the behavior of while loop and for loop is different?

I am trying to read user and server details from file tempo.txt and then check the disk space usage of the file system on that unix account using another script server_disk_space.sh.But I am not able ...
2
votes
3answers
10k views

How to run the most recent command on AIX?

How can I run the most recent command again from history in AIX Server? And how to edit the most recent command and run it again in AIX?
0
votes
1answer
1k views

Unable to loop through cURL command

I am able to execute individual cURL commands using, curl -u user:password -v -XPOST -H 'Content-type: text/xml' -d '<featureType><name>quadrella_indica</name></featureType>' ...
0
votes
4answers
968 views

Bash Globbing Variable Substitution? [duplicate]

Possible Duplicate: Batch renaming files I want to rename files using their existing name as a base for the new one. So if I can ls these files with ls blue*+(.png) I'd want to rename them ...
9
votes
2answers
4k views

xargs : using same argument in multiple commands

Am trying to write a one-liner that can probe the output of df -h and alert when one of the partitions is out [or almost] of space. It's the part using xargs that kicking me in the ass now... echo 95 ...
6
votes
5answers
15k views

How to exit sh program?

I bungled the commands and wrote sh -man Now I've entered a program called sh-3.2 that is seemingly impossible to exit. Ctrlc,Ctrlz, or Ctrlxdoes not work. exit, quit, q, :q also does not work. ...
2
votes
1answer
522 views

Execute shell script directly, without .sh file

Should it be possible to just write something like for i in 1 2 do echo $i done in the command line and have it run? Because when I try to do this, nothing happens but > being printed each time I ...
4
votes
4answers
608 views

List any file ending with .in and corresponding .out with shell script

I have a directory full of files ending with different extensions, how would I list/select only the files ending with .in and corresponding .out that share the same basename? e.g. file1.txt file1.in ...
1
vote
1answer
672 views

How do I tell whether I'm in a non-login shell or a login shell? [duplicate]

Possible Duplicate: How to check if a shell is login/interactive/batch And what's the benefits of non-login shell over login shell?
3
votes
1answer
650 views

Make stdout and stderr be buffered by the same buffer

Is it possible to force glibc to use the same buffer for stdout and stderr? If I tee the both outputs: ./tests/tests 2>&1 | tee log I get mixed messages (i.e. messages are ordered inside ...
2
votes
2answers
2k views

Sort the output of find before piping to openssh

I'm using this command to recursively generate a SHA-512 hash for each file in a directory hierarchy: find . -type f -exec openssl sha512 {} \; I'd like to sort the files in lexicographical order ...
3
votes
1answer
735 views

Redirect all standard out for rest of script

I have a bash script that I want to redirect all the rest of the output into a file. #!/bin/bash # the part i dont know ${file} echo spo echo car cat ${file} output should be spo\ncar\n
2
votes
3answers
6k views

How can I use grep to search for lines that start with a certain character in bash

I want an alias ('ggg') that will look through my existing set of aliases and tell me all the ones that begin with g. I have a lot of g* aliases :) I tried this: alias ggg='alias | grep ^g' but didn'...
1
vote
3answers
3k views

How to run a Python script in Makefile

I want to write a Makefile to find specific files and run a Python script on each file. The Python script accepts sys.stdin input. find $(W)/$(OVE) -name "*.xml" -print | \ while read x ; do \ cat $...
31
votes
4answers
7k views

What's the difference between running a program as a daemon and forking it into background with '&'?

What are the practical differences from a sysadmin point of view when deploying services on a unix based system?
4
votes
2answers
2k views

Colorizing tail output with sed

How would I go about colorizing the output of tail with sed? echo "`tput setaf 1`foo`tput op`" works as expected echo "foo" | sed -e 's/(foo)/`tput setaf 1`\0`tput op`/g' however, does not. What am ...
14
votes
1answer
2k views

How to copy from/to the tmux 'clipboard' with shell pipes?

When working in a shell environment I run fairly often into the need to copy 'intermediate pipe output' around (eg. from/to already running editors, to other shells, other machines, etc.). When in a ...
41
votes
3answers
83k views

How do I set an environment variable on the command line and have it appear in commands?

If I run export TEST=foo echo $TEST It outputs foo. If I run TEST=foo echo $TEST It does not. How can I get this functionality without using export or a script?
15
votes
8answers
1k views

Suggested setup for an ultra-lightweight text-based programming environment in linux

I am looking for suggestions for a setup for my particular needs. I haven't done much linux since college and want to get back into it as a hobby. I have some not-too-powerful hardware (512 MB ram, ...
3
votes
3answers
9k views

Count running processes using wc and ps

I tried using ps r > log | wc log but this returns Ambiguous output redirect.. Can someone explain why and provide another solution?
2
votes
2answers
104 views

Create a link but don't change the canonical path

In each users' directory there exists a symbolic link to /var/www/website/public_html/. However, whenever a user cds into the link, he sees the path as /home/username/public_html/. Is there any way to ...
10
votes
2answers
2k views

Command line prediction

I've found an interesting paper: Predicting UNIX Command Lines about command-line prediction (based on user past activity), and I wonder if any actual implementation of such thing exists?
1
vote
1answer
127 views

What is the difference between who > lp and who | lp?

Why does the who > lp creates a file but who | lp leads the output to program lp? What is the underlying principle behind these two simple commands? Can somebody explain it with an example?
4
votes
2answers
1k views

Log number of keyboard hits

How can I log a keyboard hit via shell script? My aim is to log the number of keyboard hits of a login session on my Ubuntu system. Note: I do not want to log the keystrokes itself, only the number ...
1
vote
2answers
693 views

How to run linux process and come back to it later?

I'm trying to run a minecraft server on linux. Running the server starts an important interactive session. I can run the server in the background by appending & at the end of the command and log ...
2
votes
2answers
100 views

`cd` all screens to the PWD of the current screen

Suppose that I am running screen on a remote server with four open screens. Is there a quick way to cd all the screens to the working directory of the currently-open screen?
2
votes
2answers
195 views

Where to place a Bash shell redirection for a command? [duplicate]

Possible Duplicate: Order of redirections Apart from the standalone exec >&2 to redirect the current shell's input and output are there any behavioral differences in the following ...
1
vote
4answers
257 views

Zsh: dirs in reverse order

I am a bit confused about how dirs works. The documentation says: dirs With no arguments, print the contents of the directory stack. Directories are added to this stack with the pushd ...
2
votes
1answer
298 views

How to make a permanent variable

In terminal: VAR="Extremely long and often used command" echo $VAR Output: Extremely long and often used command So far it works fine, but after restarting a terminal my variable doesn't ...
23
votes
5answers
18k views

What's the easiest way to find an unused local port?

What's the easiest way to find an unused local port? Currently I'm using something similar to this: port=$RANDOM quit=0 while [ "$quit" -ne 1 ]; do netstat -a | grep $port >> /dev/null if ...
0
votes
2answers
801 views

put rows of numbers into a column with shell script

I have a file with many lines, like 1 jfkdajfd 1 2 3 5 2 fkldfjld 3 fdkfloaf 9 10 4 fldfldkf 5 fdskf;ak 12 1 4 I want to get all the numbers and put them in a column in a file, like 1 ...
4
votes
1answer
2k views

intersection of two files according to the first column

I have two files in file A, there are sequence_numbers in the other file B, there are many columns, and the first column is sequnce numbers, I want to get a files with all the lines in the B with the ...
1
vote
1answer
2k views

busybox ash PS1 not expanding

I am trying to setup busybox's ash on an embedded system to support expanding the PS1 prompt statement. I have it currently set as PS1='\u@\h:\w\$ ' However, all that is displayed is literally \u@\...
1
vote
1answer
156 views

How can I have cd show the directory it switches into?

I have made my command prompt ($PS1) to be just username.../current_directory (using the 3 dots because my directory structure has lots of levels and they were taking up too much of the command line ...
2
votes
2answers
156 views

Parameter splitting

I have a bash script that is a simple wrapper around another process: $ cat ~/bin/s3cmd #!/bin/sh trickle -u 80 ~/bin/s3cmd.py $* $ This works great when the parameters don't contain spaces. ...
3
votes
2answers
764 views

Limit stdout from a continuously running process

I haven't had much luck finding an answer to my problem, but maybe I'm not asking for it correctly. I have a process I startup like the following: nohup ping 127.0.0.1 > log.txt >2>&1 & ...
17
votes
5answers
12k views

How can I kill and wait for background processes to finish in a shell script when I Ctrl+C it?

I'm trying to set up a shell script so that it runs background processes, and when I Ctrlc the shell script, it kills the children, then exits. The best that I've managed to come up with is this. It ...
19
votes
1answer
991 views

Why doesn't 'find' show this file?

Using find with grep, one can locate files that match a pattern: # find | grep error ./solr-modifiedSolr4/SolrPhpClient/phpdocs/errors.html ./error_log ./includes/classes/error_log However, using ...
31
votes
6answers
15k views

Is there a program that can send me a notification e-mail when a process finishes?

I am a computational scientist, and I run a lot of lengthy calculations on Linux. Specifically, I run molecular dynamics (MD) simulations using the GROMACS package. These simulations can take days ...