The shell is unix's command-line interface. You can type commands in a shell interactively, or write scripts to automate tasks.

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5
votes
2answers
62 views

Default preference of executable over built-ins with the same name

I was playing around a bit with the names of some executables, putting them in a folder, ~/bin, which is in my $PATH. Now I'm wondering how I can set the preferences of a bash-3.2 terminal so that it ...
1
vote
3answers
302 views

php shell_exec() permission on Linux Ubuntu

I'm developing a php application using Linux server. My problem is executing shell_exec() to call some exe file is not work(actually not exe, it's kind of linux executable file) echo ...
3
votes
2answers
119 views

Unit multiplier conversion in a shell script

I need to convert human-readable sizes into bytes. Unfortunately numfmt function is not accessible for me. Is there any other alternative? I need a shell/bash function to call from inside the sh ...
-2
votes
1answer
28 views

Implementation Logic [closed]

I have two files,which is something like this: file1 msgid "New" msgstr "" dsvhuvchvdhcvhc msgid "Old" msgstr "hsvhs" kdnvcjdbvj msgid "Bold" msgstr "" file2 dcbjdsbc msgid "New" msgstr "Alas" ...
-1
votes
4answers
58 views

Using 'find' to create text file, and later deleting files listed

I'm trying to use find to create a text file with the result. And then later be able to delete files, based on that list. I'm using find /volume1/video/ -iname "sample" to give me the results. How do ...
1
vote
1answer
29 views

Pressing tab after sourcing script file prints script related output

I have a script file in a directory. Its contents are as follows : #!/bin/bash ...
1
vote
0answers
55 views

What happened with my SHLVL? [closed]

I was messing around with my bashrc, finding better ways to start a newer version of bash. Never mind my tests. But this strange thing happened, which I like to understand: $ bash ## Probably where ...
1
vote
1answer
78 views

How to get the JSON STRING from the given string

I have a string given below. I just need to get the first accountHeader (bolded) JSON string, I tried everything.. It didn't work. Can you help me to get the data? <START ...
0
votes
0answers
40 views

usermod -L after creating the home dir

so I see from some questions here, to lock an account, create it, then lock, e.g. useradd -M lol;usermod -L lol However.. I do have a home dir, by eg. useradd -md /path/lol Question is.. to avoid ...
3
votes
1answer
108 views

How can I forward a already forwarded ssh key into tmux?

I'm connecting through SSH from a machine where my keys are stored, forwarding to a second machine, and then try to use the keys from within tmux. I appear to "loose" the forwarding when entering ...
1
vote
2answers
42 views

Make Trickle get the correct $PATH

Trickle is a bandwidth limiting program. I have the following script for trickle. #!/bin/bash echo $PATH trickle -s -t 3 -u 200 -d 200 "$@" I have a script in ~/bin/ that want to run the script ...
2
votes
1answer
58 views

< and << in UNIX /Linux

What is the option <<and < are used in linux for??? For example cat << abc.txt I know its a stupid question, but i was not able to search it on google as i did not know what ...
13
votes
2answers
2k views

Why can't I do ls *.txt in a subshell?

~$ echo $(ls) arguments.txt cecho.sh Desktop Documents Downloads example.txt Music Pictures Public ~$ echo $(ls "*.txt") ls: cannot access *.txt: No such file or directory Why does the ...
3
votes
7answers
387 views

Batch renaming of files [duplicate]

I have a directory full of images: DSCN4749.JPG DSCN4750.JPG DSCN4892.JPG ... And I would like a one-liner to rename them to (say). dscn4749.jpg dscn4750.jpg dscn4892.jpg ... How do I do this? ...
2
votes
1answer
76 views

How to find the path of your current working directory?

How can you find what the is the path of the current working directory?
1
vote
1answer
17 views

Search for all messages containing a sring only in those files which is mentioned in a text file

You are in a directory with a large number of FIX logs that are over 1GB in size. You have a text file containing the names of 10 of those files. How can you search for all messages containing ...
2
votes
1answer
36 views

Compressing all files that contain a particular string

How can you compress all files in a directory that contain the word “compress” anywhere within its contents?
0
votes
2answers
44 views

Handling files with whitespace in their names

I have a lot of files that I need to sift through, specifically grep for certain keywords IN THE FILE, not he FILENAME. I have some 300+ files on a filesystem (so the files are within multiple ...
1
vote
2answers
54 views

What's the meaning of a dot before a command in shell?

While following android eclipse debug tutorial, I encounter following commands. cd /path/to/android/root . build/envsetup.sh lunch 1 make emulator My problem is what the dot before ...
6
votes
3answers
381 views

is it possibe to change parent shell's working directory programmatically?

I want to write some code to allow me switching to some directories that I usually go to. Say this program is mycd, and /a/very/long/path/name is the directory that I want to go to. So I can simply ...
4
votes
1answer
73 views

Can redirecting stdout and stderr to the same file mangle lines?

I've read that when redirecting stdout and stderr to the same file using 2>&1, stdout is usually block buffered while stderr is unbuffered. If a very long line is written to stdout, requiring ...
0
votes
1answer
48 views

shell unexpected end of file error

I had the below script working in a linux machine. page="$(curl http://www.google.com/| grep "title")" if [ -z "$page" ]; then echo "Empty page" else echo "Valid page" fi When am running in ...
2
votes
4answers
85 views

Incrementing a variable each time the system boots up

The idea is to initialize a variable and set it to 0. Then create a script that executes on boot and increments that variable by 1 each time the system boots up again. Sounds simple enough right?
2
votes
3answers
545 views

How to merge two files based on the matching of two columns?

I have file1 likes: 0 AFFX-SNP-000541 NA 0 AFFX-SNP-002255 NA 1 rs12103 0.6401 1 rs12103_1247494 0.696 1 rs12142199 0.7672 And a file2: 0 AFFX-SNP-000541 1 0 ...
5
votes
3answers
193 views

How to merge two files with different number of rows in shell?

I have file1 like this: CHR SNP TEST A1 A2 GENO O(HET) E(HET) P 0 AFFX-SNP-000541 ALL 0 0 0/0/0 ...
4
votes
3answers
202 views

Please help explain this bash output redirection

This script was posted as answer to a Question. And I'm trying to work out what's going on. result=$( { { ssh host app-status >&3 3>&-; echo "$?" } | { until read ...
2
votes
2answers
176 views

Do I need to encapsulate awk variables in quotes in order to sanitize them?

As per an answer on stackoverflow, it's my understanding that encapsulating bash variables in double-quotes is a fairly safe way of sanitizing user input. What about awk variables? For example, if ...
1
vote
3answers
113 views

A command which returns either a process ID, if running, or some other output if not?

I'm looking for a command that will give me the PID, and it's not running it should give me some output other than blank. In my program, sometimes the library I'm using gives blank output even if ...
0
votes
1answer
61 views

set tab color in a tabbed terminal emulator

I would like to set in my terminal emulator (i.e. gnome-terminal) the color of the tabs like in the osx's terminal emulator. Is there this feature in any of the linux terminal emulator plethora? ...
0
votes
2answers
50 views

What does the `set $variable` do?

I know that set is used to manipulate environment variables, but I want to make myself sure - these alterations are not permanent, right? I mean once I close shell and reopen it, no changes will be ...
0
votes
1answer
68 views

Can I use an if statement to detect if bash and dash are being run interactively? [duplicate]

After looking around for a while I've found several good pages describing how to check and see if a bash script is running interactively and there seem to be several methods, but one of them that I ...
2
votes
1answer
53 views

Using LDAP for authentication, how can I safely disable/deactivate an account without deleting it?

We use LDAP for authentication for thousands of users. The primary tactic we have been employing to make a user unable to login, without removing their account, is to change the LDAP attribute ...
3
votes
2answers
57 views

How can I make shell aliases available when shelling out from Vim?

In my .zshrc, I declare some aliases. Eg, which dbstart shows the contents of that alias. If I open vim from that shell, it is a child process. In Vim, I can run shell commands with :! some_command. ...
-9
votes
2answers
120 views

Unix Script that has no wc command [closed]

Write a shell script that count number of regular files having execute permission under current directory. [Do not use wc command.]
7
votes
4answers
266 views

Grep from the end of a file to the beginning

I have a file with about 30.000.000 lines (Radius Accounting) and I need to find the last match of a given pattern. The command: tac accounting.log | grep $pattern gives what I need, but it's too ...
3
votes
1answer
104 views

Using shell's read command with live editing functionality (readline like)

Is there a standard (POSIX) way of asking the user some data from within a shell script, with read for example, while allowing live edition of the text being typed (what readline does)? I know bash ...
3
votes
1answer
117 views

Why does grep treat '[D]ebug' string differently?

I've created simple text file named "T" to test the unusual behavior of grep: 1 Debug 2 debug 3 determined 4 Determined Tried different syntax: $ grep De T 1 Debug ...
2
votes
2answers
83 views

delete directory with special character in filename

I have these tricky directories that I can't figure out how to delete. If I run ls -ld * I get… drwxrwxr-x 7 user1 taskfmri 2048 Jan 22 15:26 857263 drwxrwx--- 4 user2 ...
2
votes
2answers
84 views

Extracting parts of filename

I'm trying to use a part of the file name to be inserted into a new file created using the script. For eg: dcn_2014_01_31_14_17_45_505.pcap and dcn_2014_01_31_14_32_27_656.pcap should give ...
1
vote
4answers
74 views

How to get started with bash? [closed]

I need a way to be able to run a script that will automate terminal commands, one after another. As I understand it, this is exactly what bash does. (Am I right, even on this count?) Where can I ...
0
votes
1answer
40 views

How I append the data of Multiple files into one file?

I want to append data of approx 500 files into one file and each of these files are located in their respective dirs. Also How i can verify the contents of merged file e.g How i verify that data ...
0
votes
1answer
35 views

How to measure rlogin time?

I need to monitor the time it takes to rlogin from one HP-UX machine to another. So I wrote this: #!/bin/sh result=`rlogin 10.10.10.1 << EOF exit EOF` result2=`{ time $result >/dev/null; } ...
2
votes
1answer
57 views

indirect variable expansion in POSIX as done in bash? [closed]

Is it possible, or is there some elegant hack to do indirect variable expansion in POSIX as can be done in Bash? For context, I'm trying to do the following: for key in ${!map_*} do # do ...
2
votes
2answers
69 views

How to split files with common prefix in bash

I have a directory with many files with common prefix, like gsc*_other.foo, where * is a character that goes from 0 to 9 or a/b (where a stands for 10 and b for 11). My goal is to create text files ...
3
votes
2answers
664 views

Mysql query resultset in bash script

I am using the bash script to connect to the mysql database and execute a query. I use the below script to connect to the database and execute the query. #!/bin/bash Total_Results=$(mysql -h ...
3
votes
2answers
110 views

Save find -exec output to text file

I have a set of videos in the folder. I would like to get the info about this videos using ffmpeg -i command and save the output to file. So I wrote the line: find . -type f -exec ffmpeg -i {} \; ...
1
vote
1answer
19 views

Timestamp ts not working with thinkfan

I wanted the output of thinkfan -n output with a timestamp next to it so I can later analyse the patterns, and found this question: Prepending a timestamp to each line of output from a command, which ...
2
votes
3answers
23 views

Move line from output to the front of output or custom reordering

I have a command find "$PWD" -name __openerp__.py|awk -F/ -vOFS=/ 'NF-=2'|sort -u and I want to take a certain line containing /web/addons and push it to the front of output then do the same with ...
0
votes
1answer
157 views

How to execute Netscaler commands through a remote machine via SSH connection

I have been trying to execute some NetScaler commands like "bind" & "unbind" through a Linux Box via an SSH Connection. Now the Problem is, Manually we are able to enter & execute commands on ...
2
votes
4answers
68 views

print parent directories full path of find output

what I want to do is to find all files based on some search query and get parents parent directory (../..) full path. For example find . -name "__openerp__.py" and then for each file execute ...