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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6
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2answers
3k views

Is there a unix command line tool that can analyze font files?

Given a directory of font files (TTF and OTF) I'd like to inspect each font and determine what style (regular, italic, bold, bold-italic) it is. Is there a command line tool for unix flavored ...
4
votes
1answer
1k views

How to produce a file encoded in Mac OS Roman

Inside a bash script I have a line that creates and then inside a loop, append strings to a text file, something like echo $myTextString >> file.txt I need this final file to be formatted ...
22
votes
2answers
34k views

How to check if there are no parameters provided to a command?

How do you check if $* is empty? In other words, how to check if there were no arguments provided to a command?
0
votes
2answers
5k views

clear tmpfs in my case

I am on a Ubuntu machine. I have make a directory under root directory, by: $ sudo mkdir /hello $ sudo mkdir /hello/bye Then I mount tmpfs with size 1024M to /hello/bye by: $ sudo echo "tmpfs ...
1
vote
3answers
151 views

Transferring access privileges from root to regular user

I log in to Ubuntu with the username student. There are some directories only the root user is allowed to access, for example /var/lib/mysql, (I know I can use sudo to access it but it is not what I ...
1
vote
3answers
482 views

Is there a way to beep when tail -F stops to fetch new results?

A few days ago I asked Is there a way to make tail -F beep? Now I want to know if there is any way to use *nix utilities, to beep when a tail -F stops returning new lines for a while! I know, I ...
6
votes
2answers
2k views

Pasting from clipboard to vi-enabled zsh or bash shell

I'd like to be able to paste from the system clipboard (or text selection) into my "vi-like" shell prompt using the keyboard. I normally use zsh and sometimes bash. In both cases, I have the shell set ...
2
votes
2answers
4k views

How to execute this particular shell command from Python?

OK, so, I have this non-functional shell script, which I am rewriting piece by piece in python, except I am getting an "unexpected "|" error" from the shell (see below): #/bin/sh LINES=`cat $@ | wc ...
2
votes
3answers
3k views

shell commands to check & create dir

I am writing a Ruby script inside which I would like to invoke/execute some shell commands. The shell commands I would like to run should check if a directory named 'tmp' under /var/lib/mysql/ exists ...
0
votes
1answer
262 views

Is there more, less, or equal overhead for elisp, as for a bash script, to call awk, ps, etc?

Hopefully the question explains itself well enough. I'm referring to exta time and system resources involved for one vs. the other... I tend to think it would be the same, but I want to go beyond just ...
4
votes
2answers
1k views

mv on a glob pattern does not work without sudo

I am using MySQL database on Ubuntu machine. My MySQL data directory is /var/lib/mysql/ , since I have a database named "db_test" , so, I have a directory named db_test/ under /var/lib/mysql/ . And ...
3
votes
1answer
692 views

How to save the results from ls to a command?

I want the results from an ls to be saved in a var inside a makefile the command is simply the following: ls text* and the result suppose to be something like : text1.txt What i put in my script ...
8
votes
3answers
4k views

What does : ${param:=value} mean?

I read the following in A User's Guide to the Z-Shell: A synonym for ‘true’ is ‘:’; it’s often used in this form to give arguments which have side effects but which shouldn’t be used — ...
3
votes
2answers
4k views

How to reinstall /bin/sh

I have accidentally deleted /bin/sh, and I am trying to to re-install it. If I type sh in the terminal, It says The program 'sh' can be found in the following packages: * bash * dash If I try to ...
1
vote
2answers
1k views

Running any kind of login script when sh is linked to bash

My problem: My web host offers ssh to their shared server. I want to set up a couple of aliases and such, so I'm trying to get a login script of any flavor to run. If my shell was plain bash, I would ...
3
votes
2answers
963 views

Simple shell script needed to move database files

I am using MySQL on Ubuntu machine. I need to physically move around the database files under /var/lib/mysql/ (this is where all the databases directories are located). Say I have two databases, ...
2
votes
3answers
2k views

Trouble getting awk output in for loop

I'm trying to create a script that will check a website for a word. I have a few to check so I'm trying to input them via another file. The file is called "testurls". In the file I list the keyword ...
7
votes
2answers
358 views

Why does 'for anytext; do' loop four times?

Is this a bug or a feature? It seems to happen for unquoted alphanumerics. Running GNU bash, version 4.1.5 for alpha01234; do echo $((++i)); done output: 1 2 3 4
4
votes
1answer
804 views

Fetching user input while running in the background

I am writing a script that prompts the user for input and does some processing afterwards. I was using read to get the data, but then I noticed that when the script is ran with a keyboard shortcut (I ...
28
votes
5answers
50k views

Script to monitor folder for new files?

How do I detect new files in a folder with a bash script? I would like to process the files as soon as they are created in the folder. Is this possible to do so or do I have to schedule a script with ...
3
votes
3answers
2k views

Where do background jobs go?

From gnome-terminal I know the ability to suspend a job with C-z, and then send it to the background. When I close the terminal the process does not end. Where is the job being managed from, or is it ...
1
vote
1answer
213 views

Delete zsh auto completion suggestion

When I use tab-completion in zsh, the shell suggests me files and I discover that I'm in the wrong directory. How can I just delete the suggestion instead of backspace'ing it?
2
votes
2answers
1k views

How do I echo a command and include line returns?

I am writing a bash script, and on a condition I'd like to output ps aux --sort -rss However, when I write : echo `ps aux --sort -rss` everything is on one huge line. How do I run it so it outputs ...
3
votes
2answers
3k views

How to fix bash looking for a program in the wrong dir (Issues setting up NPM on Ubuntu 11.10)

This time I ran the "trusting" install script curl http://npmjs.org/install.sh | sudo sh from the dir /. $ which npm /usr/local/bin/npm $ npm bash: /home/steven/local/bin/npm: No such file or ...
1
vote
2answers
232 views

How to timestamp a transcripted talk?

I'm trying to mark each paragraph of transcripted text with timestamps of when/where it occurs in the audio. mplayer and emacs are getting me close. mplayer, in the terminal, outputs a stream of ...
1
vote
3answers
472 views

Returning a portion of a line matching a pattern

I have a file (file_name) which contains exactly one occurrance of the string "Result: " at the start of a line. I want to print all the characters after the string "Result: " in that line until I ...
15
votes
8answers
21k views

How to compare to floating point number in a shell script

I want to compare two floating point numbers in a shell script. The following code is not working: #!/bin/bash min=12.45 val=10.35 if (( $val < $min )) ; then min=$val fi echo $min
15
votes
3answers
25k views

Confusing use of && and || operators

I was skimming through an /etc/rc.d/init.d/sendmail file (I know this is hardly ever used, but I'm studying for an exam), and I've become a bit confused about the && and the || operators. ...
9
votes
4answers
23k views

Why is echo ignoring my quote characters?

The echo command isn't including the complete text that I give it. For example, if I do: $ echo ' echo PARAM=` grep $ARG /var/tmp/setfile | awk '{print $2}' ` ' It outputs: echo PARAM=` ...
2
votes
1answer
1k views

find command with -execdir not reading flags?

I am trying to locate all .jpg picture files in my current directory and sub-directories and move them to another directory. I want the source files to overwrite the destination files, but that is ...
2
votes
4answers
313 views

Generate lists of page numbers for 2-up duplex printing: 2,3,… and 1,4,…

How can I generate the following increments? 2,3,6,7,10,11,14,15,18,19,22,23,26,27,30,31,34,35,38,39,42,43,46,47,...,135 and ...
2
votes
3answers
2k views

cp launched from code results in cannot stat '/tmp/somedir' works in shell

I'm working on making some scripts more elegant by implementing them in a real x application etc... At some point in the scripts we basically want to take everything from a mounted removable storage ...
27
votes
5answers
17k views

Converting relative path to absolute path

Is there a *nix command to get absolute(and canonicalized) path from relative path(with current path) or symbolic link?
0
votes
0answers
284 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 ...
7
votes
7answers
3k views

Bash - Continuous String Manipulation

#!/bin/bash FILE="$(basename "$1")" FILE="${FILE/%.jpeg/.jpg}" Is there anyway to glue these two lines together into a one-liner?
6
votes
6answers
3k views

Portable way to find inode number

At first I used stat -c %i file (to help detect the presence of a jail), which seemed to work on any Linux distribution under the sun. On OS X' I had to use ls -i file | cut -d ' ' -f 1. Is there ...
29
votes
1answer
1k views

Avoiding “BASH-isms” in shell scripts

Does there exist a tool similar to Perl::Critic that will inspect your shell scripts and point out flaws, portability issues, uses of non-standard programs without fallbacks, depreciated program uses, ...
12
votes
3answers
3k views

Are two files hardlinked?

How can I tell if two files are hard-linked from the command line? e.g. something link this: $ ls fileA fileB fileC $ is-hardlinked fileA fileB yes $ is-hardlinked fileA fileC no
8
votes
6answers
3k views

Remove empty directory trees (removing as many directories as possible but no files)

Suppose I have a dir tree like this: ROOTDIR └--SUBDIR1 └----SUBDIR2 └----SUBDIR3 I am looking for a command such that when I input: $ [unknown command] ROOTDIR The whole ...
2
votes
0answers
99 views

“cd //” and “cd /” what is the difference? [duplicate]

Possible Duplicate: unix, difference between path starting with '/' and '//' If I make a cd // followed by a pwd I see: # cd // # pwd // why is that? what's the differece ...
5
votes
5answers
298 views

Is there a way to see the permissions of all the intermediate directories of a path..?

I have a file path.. Is there any single command to see the file/directory permissions of all the intermediate directories in the path..?
2
votes
3answers
2k views

Returning only the portion of a line after a matching pattern

I have a file (file_name) which contains exactly one occurance of the string Result:, at the start of a line. I want to print all the characters after the string Result: in that line until I encounter ...
1
vote
3answers
894 views

Writing a shell script to take output of an executable and perform some calculation

I am not much familiar with shell script. I want to write a shell script for the following pseudo-code: min=some garbage value for(i=1 to N){ // N and n will be taken as input for the shell script. ...
4
votes
4answers
916 views

Find a string (like grep -q) within only a section of a file

I want to write some Bash that can verify that a string exists in a configuration file. I can't change the file format, it belongs to a different application. The file is subdivided into groups named ...
4
votes
3answers
1k views

Delete matching file from every subfolder of current dir

I used this one to copy file in every dir: find -type d -maxdepth 1 -print0 | xargs -0 -n1 cp .htaccess Now i need to do reverse one and delete file with matching name from every sub directory of ...
23
votes
4answers
20k views

How do I exit a script in a conditional statement?

I'm writing a bash script where I want to exit if the user is not root. The conditional works fine, but the script does not exit. [[ `id -u` == 0 ]] || (echo "Must be root to run script"; exit) ...
2
votes
1answer
627 views

How to insert a first column to many files + how to convert unix time to normal time

There are many-many files in a directory that has e.x.: the following content: INPUT: root 1324711901 sshd 1272725792 And I'm searching for a solution how to convert the content of the ...
9
votes
5answers
7k views

Run script in a non interactive shell?

I have a cron job that is running a script. When I run the script via an interactive shell (ssh'ed to bash) it works fine. When the script runs by itself via cron it fails. My guess is that it is ...
1
vote
1answer
73 views

Program to upgrade configuration files

When upgrading Ubuntu (and probably other *nixes), the upgrade process will show a diff of changed configuration files and ask whether I'd like to replace them, keep the old version, or manually merge ...
5
votes
2answers
7k views

How to get a clean environment in a ksh shell?

I need to get rid of all the environment variables in a Ksh shell. I can fork a new instance, but it will inevitably source some init files (as far as I know .profile, .kshrc). Is there a way to ...