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
33 views

How to build space separated, escaped full paths of files recursively matching glob?

I have a program which requires paths to files as arguments, which cannot be quoted and must not depend on working dir. Can this be done without chaining multiple xargs, tr, find, readlinks? Example ...
0
votes
1answer
18 views

paths for searching executables [duplicate]

My old xournal is 0.4.5, which is /usr/bin/xournal. I just installed a new version 0.4.8 by compiling from source to /usr/local/bin/xournal. When I call xournal directly from the terminal, it is the ...
3
votes
1answer
80 views

Is there a way to pass a variable from an awk statement to a bash function as an argument? [closed]

I am trying to look a for some specific values from (such as 1 or 4 and 2 or 3) a text file using an awk statement in a bash script. If this value is found in the file (within the awk statement), then ...
4
votes
3answers
290 views

awk with if statements

I am trying to print from a file using awk, but my output is empty. Here is my code so far accountNum=$1 while read -r LINE || [[ -n $LINE ]] ; do awk -F',' '{ if($1==accountNum) { print ...
14
votes
3answers
992 views

What does it mean to be “sh compatible”?

I've seen the phrase "sh compatible" used usually in reference to shells. I'm not sure if it also applies to the programs that might be run from within shells. What does it mean for a shell or other ...
10
votes
2answers
334 views

Strange difference between pwd and /bin/pwd

I added a symlink to the current directory with ln -s . aa. If I execute cd aa, and after that I executed pwd, the response is /home/sim/aa. But if I execute /bin/pwd it prints /home/sim (the current ...
3
votes
1answer
55 views

Grepping a variable

I've written a simple init script to start and stop a Python script as a service. I have to be explicit about the version of Python I'm running, because this is on a CentOS 5 box with Python 2.4 & ...
4
votes
3answers
185 views

Regex alternation/or operator (foo|bar) in GNU or BSD Sed

I cannot seem to make it work. GNU sed documentation says to escape the pipe, but that doesn't work, nor does using a straight pipe without the escape. Adding parens makes no difference. $ echo ...
2
votes
1answer
66 views

Renaming the files and move to other path

I need to rename the files given below and move to some other path 1234551abcde20140718023216001.txt.809047512.2014_07_07_13:47:44 000001abcde20140718023216001.txt.34568.001.2014_07_07_13:50:44 ...
4
votes
5answers
119 views

Add leading characters infront of string using printf or echo

How can I add leading characters to fill a string to a certain length? Assume I want to add zeroes infront of a string, if said string is shorter than 20 characters: printf '%020s\n' "$line" ...
0
votes
1answer
37 views

Must pass urls in quotes

I'm trying pass a URL to mpv for it to play it as a network stream. This can be done in bash with the following syntax: $ mpv http://myvideosite.com However, zsh wants to evaluate the URL as ...
1
vote
2answers
26 views

Shell is option given

I have a couple of arguments inside a list (array, e.g. $@) and I'd like to know if the option -v is in the list. In Python I would simply do: verbose = "-v" in sys.argv How do I achieve that in ...
2
votes
1answer
54 views

How can I get this script file's functions to load without having to source it every time? “command not found” (Bash/scripting basics)

How can I get this script file's functions to load without having to source it every time? I created a file foo with script functions I'd like to run. It's in /usr/bin, which is in the PATH. File ...
1
vote
1answer
56 views

Verify the length of a variable

I've to verify the length of variable read (my script limit to five the characters inserted), I think about something like this: #!/bin/bash read string check=${#string} echo $check if [ $check -ge 5 ...
2
votes
3answers
48 views

Looking for a way turn multiples commands with same parameter into a one liner

I sometimes end up doing things like: Example: from ~/blah $ mkdir ~/test-tmp $ cp * ~/test-tmp $ cd ~/test-tmp using the destination dir 3 times in a row. Isn't there a way to turn these into a ...
4
votes
1answer
80 views

What exactly is 'scrollback' and 'scrollback buffer'?

What are "scrollback" and "scrollback buffer" in programs like bash and screen, and how do they relate to the tty, the programs being run, and stdin/ stdout/ stderr? Here is the only definition of ...
6
votes
2answers
307 views

How to find out which program can open a given file?

Let's say I have a file thesis.pdf or picture.jpg Is there a command which returns a program to open this file with? I am aware of the command file, but it just returns the correct type of the file ...
1
vote
3answers
100 views

How do I Copy and Paste lines between a start and end keyword?

I have two text files, and I want to copy a bunch of lines from one to the other. File one has a list of packages, and I want to copy it to list two. This list of packages isn't at the start of file ...
4
votes
2answers
89 views

How to redirect stdout to a file and read from the same file simultaneously with another task?

I want to run a task (which takes quite a long time) remotely in Ubuntu Linux Bash via nohup and redirect stdout to a file, e.g.: nohup task > out.txt & From time to time I would like to ...
2
votes
1answer
67 views

Backslash with pipe in system command from awk

I want to invoke shell command from awk so I am using system() but when I am passing expression in I am getting error at backslash. Here is my expression echo "select * from abc limit 1;"| ...
0
votes
2answers
25 views

concatenate .out files

Can I combined multiple .out files with the cat command in bash or csh? Additionally I want only the header of first file to be concatenated and I was thinking of using the tail function for that. ...
2
votes
3answers
236 views

Shell script not executing

Not sure what is happening. Lets call script a.sh with the following /users/guru$ cat a.sh #! /usr/bin/ksh echo "Hello" date Execute with ksh. It gets done. /users/guru$ ksh a.sh Hello Tue Jul ...
0
votes
1answer
352 views

Bash script question - skip enter key press [duplicate]

Here is a portion of my script: read main_menu case "$main_menu" in "0" ) exit ;; "1" ) cp /etc/bamt/cgminer.conf.X11 /etc/bamt/cgminer.conf; sudo mine restart; ...
4
votes
2answers
136 views

Add arguments to bash -c

Let say that I want to run a command through bash like this: /bin/bash -c "ls -l" According to bash man page, I could also run it like this: # don't process arguments after this one ...
1
vote
1answer
40 views

Bundling of dependencies with shell scripts

Shell scripts often have to depend on tools that may not be installed on the users' computer. To circumvent this problem, many scripts have multiple fallbacks. IMO doing such things only leads to ...
4
votes
2answers
146 views

Get specific line from command output in awk

I have used pipeline to read specific record from impala shell.Here is what I got [cloudera@localhost ~]$ echo "select * from abc where key > 'a-26052014015400' limit 1;" | impala-shell Starting ...
16
votes
1answer
906 views

What does the @ (at) symbol before a filename mean in a curl command?

I am looking at an example of a curl command that uses the @ symbol before the filename to post data to the server. curl http://localhost/ --data-binary @file.txt What does this mean? Does it ...
4
votes
3answers
146 views

Write text messages between Unix and Windows

Is it possible to send text messages between two users of the same LAN, but the first running Windows with cmd and the second running Linux/Unix? I am not looking for an instant messaging service. I ...
4
votes
1answer
160 views

Keep getting the same result after “export PATH”

I am doing this: $ which cabal /usr/bin/cabal $ export PATH=$PATH:$HOME/.cabal/bin $ which cabal /usr/bin/cabal I expect to get /.cabal/bin/cabal for $ which cabal (this path exists) after this. ...
3
votes
2answers
137 views

Getting the current path in .desktop EXEC command

Im trying to make a .desktop file run a .sh which is stored in the same directory as the .desktop. The whole directory needs to be portable and moved from machine to machine. my run script is run.sh ...
2
votes
2answers
128 views

How to force watch to run under bash

The problem is that when watch is executed it runs sh and I get this error: sh: 1: func1: not found here is the code: #!/bin/bash func1(){ echo $1 } export -f func1 watch func1
3
votes
1answer
247 views

find files without extension

Let say I have: foo.txt bar baz.ooo If I use ls -1 !(*.*) then I'll get only bar on the output. Great, now I wish to have same results with find - some find -regex that will do the job. NOTE: ...
0
votes
0answers
36 views

How to return multiple select count in an array variable in shell

I have a 4 SQL count values which I want to return in an array record_count so that I can use that count values in some if statements later in the shell program. But I am not able to return the values ...
0
votes
0answers
14 views

command type “hashed”? [duplicate]

type displays information about a command's type. How would it be interpreted if used as a command name? What command "types" are there? In the following example, what does "hashed" mean? Is it ...
0
votes
1answer
43 views

What is “built-in” command in bash [duplicate]

cd is a built-in command in Bash. Is a built-in command or function in Bash the same concept as a built-in command or function in an interpreter language (e.g. Python)? Is "built-in" a concept of ...
1
vote
3answers
96 views

Problem when splitting command with backslash in unix prompt

I often use the space-backslash combination ( ) to split a command and its parameters into various lines and make it more readable: /home/user> ls -ltra \ > file1.txt \ > file2.txt ...
1
vote
1answer
40 views

svn: add all my new files and directories

I'm using Solaris 10. I need to add to SVN everything I've placed in the sub directories of my SVN checkout. I have added files and directories and sub directories - is there a command to take care of ...
7
votes
4answers
686 views

What is the source of help?

help displays information about builtin commands. What is the source of help? Does it maintain a database for builtin commands, or does it read some files of each builtin commands (similar to the ...
1
vote
1answer
34 views

How to slice a text file into several files of 100 lines each? [duplicate]

My question might be quite unclear here. I have a giant text file with values that looks like this 0.00601233 0.000139403 0.000133679 0.000139497 0.000141683 0.000141888 0.000138646 0.000133465 ...
3
votes
1answer
78 views

Why does the read command not take interactive options when run by sh?

I want to download a provisioning script that reads some configuration parameters via read, and execute it: curl http://example.com/provisioning.sh | sh The problem is, that the read command in the ...
1
vote
2answers
37 views

what's the right pattern to match my command

OS: AIX 7.1 I am working on a shell script which let user input some command and execute it, one of the commands is in this form: compile appname the appname only can be one of [ccms|asws], what's ...
0
votes
1answer
61 views

What is the difference between ~ and / in paths [duplicate]

When I first log in to Unix on my Mac, I usually see a ~ after my username in the command line. However, if I look at the apps contained in that directory ~/Applications they are not all of my ...
11
votes
3answers
635 views

Is there any major difference when comparing a variable as a string or as an int

Out of curiosity, when doing a bash variable comparison (its value being an integer) it's possible to test it against some predefined value either declared as an int or as a string. Sample script: ...
2
votes
1answer
119 views

setenv not working in tcsh

I am trying to install a program on my brand-new CentOs. The installation requires setenv, which apparently does not work, not even in the tcsh shell. Can anyone give me some advice? [Anna@anna ...
1
vote
1answer
237 views

How to run java service as a non-root user on CentOs 6

I have a script that starts a Java application as a service on CentOS 6: #!/bin/sh # chkconfig: - 80 20 SERVICE_NAME=cn4server PATH_TO_JAR=/usr/local/share/myserver/cn4server.jar ...
3
votes
1answer
31 views

annotate “include” file for grep with comments?

I do a grep sort that includes certain strings. That is, give me the lines in a file that DO contain certain strings. As in grep -fv include file > out That command looks in file and sends to ...
4
votes
1answer
46 views

How to update 'command cache' after change of soft links?

I have changed multiple soft links on my system with ln -f -s. When I view the link with ls -l, I see they point to the right target. However, when I try to run the command, it still tries to use the ...
6
votes
3answers
258 views

`/proc/$PID/cwd` : is there a POSIX equivalent?

Linux has a /proc directory and file‑system, which as far as I can tell, is not part of POSIX. In each /proc/$PID subdirectories, is a symbolic link, cwd, pointing to the actual working directory of ...
0
votes
0answers
31 views

Virtual serial port problem

Background: I've to test external GSM module, connected to PC with serial port. Since I'll have to either send messages both to do more, I need to create two virtual serial port (script provided by ...
4
votes
4answers
287 views

what does $* mean in shell [duplicate]

What does $* mean in shell? I have code two function, run_command and run_test, they are called like this: if [ -n "`echo ${GOAT_COMMANDS} | grep $1`" ]; then run_command $* else run_test $* fi ...