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
43 views

Given a *nix command, how do I find where the executable is? [duplicate]

There is a command written in bash I found from documentation from people who previously worked in this project. Now I need to locate the command's source and modify it. I tried which my_command ...
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4answers
52 views

Sed substitution grouping is appending in OSX rather than the expected sub in Linux

I've got three comma separated columns. Last name, First name, social. I'm trying to capitalize all characters in the last name column using sed 's/\([^,]*\)/\U\1/' foo.file In osx this command ...
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3answers
91 views

Bash long string, no word splitting?

I want to tidy up some script with long commands, so that for example: { somecheck || somecomand "reallyreallyreallyreallyreallyreallylongstring" } &> /dev/null & becomes something like: ...
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2answers
45 views

How to search recursively in a directory for different files?

I have a x.tar file in directory /a. After untaring x.tar I got the following result: cust/ cust/01/ cust/01/INFENG/ cust/01/INFENG/scr/ cust/01/INFENG/scr/test.scr cust/01/INFENG/SQL/ ...
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2answers
449 views

How can I make xargs play nice with stdin?

$ seq 1 3 1 2 3 $ seq 1 3 | xargs echo 1 2 3 $ Mentally replace seq 1 3 with any command that lists entries one-per-line on standard out. How can I get more-or-less what you'd expect, i.e. the ...
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3answers
1k views

Why does “$(( ~33 ))” produce -34?

$ echo $(( 255 )) 255 $ echo $(( 33 )) 33 $ echo $(( ~33 )) -34 $ echo $(( ~255 )) -256 $ and my kernel is: $ uname -a Linux HOSTNAME 3.2.0-40-generic-pae #64-Ubuntu SMP Mon Mar 25 21:44:41 UTC ...
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15answers
61k views

How can I get distribution name and version number in a simple shell script?

I'm working on a simple bash script that should be able to run on Ubuntu and CentOS distributions (support for Debian and Fedora/RHEL would be a plus) and I need to know the name and version of the ...
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3answers
71 views

bash: error handling on find -exec

I was using this little script to find malformed images: find -name '*.jpg' -exec identify -format "%f\n" {} \; 2>errors.txt It worked well enough, but now I need to modify it slightly. Instead ...
45
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1answer
1k views

Security implications of forgetting to quote a variable in bash/POSIX shells

If you've been following unix.stackexchange.com for a while, you should hopefully know by now that leaving a variable unquoted in list context (as in echo $var) in Bourne/POSIX shells (zsh being the ...
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0answers
23 views

What Does the Output of “--help” Mean? [duplicate]

When using the --help option of a terminal program, a lot of output is produced. It usually starts with Usage: and then a bunch of things and brackets and parentheses. My question is, what doe the ...
1
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1answer
54 views

Running some parts of a script as an unprivileged user with shell environment

I am creating an instance configuration script that sets up a machine. I am running the script via sudo i.e. sudo run.sh. Most of the steps require root access but some of the script's steps do no ...
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1answer
45 views

Bash - Command substitution adds single quotes

I have a problem with bash behavior while evaluating grave accents. I want to run find with optional -name: find -name "*.log" works fine, but when i want to get the -name part from nested script ...
0
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0answers
41 views

Counting program fails in arithmetic test

having a little trouble with this rather basic script. This script works on Bash in my macbook pro, but not on my Linux Mint desktop, which also uses bash. I can't figure out what's wrong with it, ...
0
votes
1answer
45 views

Print file name,Modified Date and Size with Header

How do I print file size, file name and modified date with header.Till now I have come up with: find . -regex '.*\.csv' -execdir stat --printf '%n,%y,%s' {} \; How to add header and do not print ...
28
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2answers
712 views

find(1): how is the star wildcard implemented for it to fail on some filenames?

In a file system where filenames are in UTF-8, I have a file with a faulty name; it is displayed as: D�sinstaller, actual name according to zsh: D$'\351'sinstaller, Latin1 for Désinstaller, itself a ...
2
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1answer
33 views

Syntax When Combining dd and pv

I am a linux newbie; so, sorry if this is obvious to you... sudo dd if=/dev/sda bs=64k | pv --size 1.5t | dd of=/dev/sdb Does the block size for dd go on the left side of this after the input as ...
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8answers
756 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, ...
16
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8answers
34k views

List only regular files (but not directories) in current directory

I can use ls -ld */ to list all the directory entries in the current directory. Is there a similarly easy way to just list all the regular files in the current directory? I know I can use find find . ...
1
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1answer
40 views

How to recover a shell script I deleted from a specific folder in Debian 7?

So in a merry mood last night, I deleted an important shell script from my system. I mistook it for something else and figured it wasn't needed. I am trying to recover it. I have tried 'scalpel' and ...
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0answers
55 views

gdrive -bash: /usr/bin/drive: cannot execute binary file

I am processing hundreds of image files on a weekly basis and gdrive would be perfect for automatically making duplicate copies of the raw images for archive before the originals go through the ...
18
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4answers
2k views

How to know the “level” of shells I am in?

If I open a terminal like xterm I will have a shell. Then if I use ssh or zsh I will have another "level" of shell. Is there a way to know how many times I have to Ctrl+D or type exit to exit all of ...
4
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2answers
107 views

My /var/log/ is mysteriously filling up GBs in minutes! Any cure before I re-install Debian 7?

Good morning, fellow *nix enthusiasts! I have been using Debian 7 for a while now and after a recent upgrade I noticed I constantly kept running out space on my root partition. I mean to the point ...
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2answers
29 views

Background processes mix up order of shell script execution

Can someone explain me why the script echo one && echo two & echo three && echo four gives me [1] 3692 three four one two [1]+ Done echo one && ...
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2answers
30 views

Problem with using expr

I've got two strings str1="( 1 + 2 + 3 + 4 + 5 ) / 3 + 5" and str2="( 1 + 2 + 3 + 4 + 5 ) / 3 + 5 * 2" The command result=` expr $str1` returns a correct value, while result=` expr $str2` ...
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0answers
11 views

What shell extension recommends packages if command is not found and how to update it? [duplicate]

I know this question might sound a little strange but i really don't know how to describe it better. On my Debian system I have a shell extension for bash that, whenever I enter an unknown command, ...
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1answer
65 views

Running every command through another

I'm setting up a system in which any external command that does something with real effect must be crypthographically signed before before the system will execute them. The restrictions are in place ...
0
votes
5answers
113 views

Read File word by word

My problem is to read a text file word by word and recovers every word in a variable. I tried to do: while read ligne; do { for ( i=1; i<= length ($ligne); i++); do { var=$(awk '{print $i}' ...
3
votes
3answers
13k views

Pass command line arguments to bash script

I am new to bash script programming. I want to implement a bash script 'deploymLog', which accepts as input one string argument(name). [root@localhost Desktop]# ./deploymLog.sh name here I want to ...
0
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0answers
23 views

Is there a way to add a timestamp to the logs for qsub job?

I'm submitting jobs on a cluster via qsub but the error/output logs don't have a timestamp, making debugging more difficult. Is there a way to add timestamps to the logs in the bash script? Appreciate ...
0
votes
3answers
45 views

copy the contents of a variable in a text file

I know this is a stupid question but I want to know how I can put the contents of a variable in a text file. This variable is a string that I want the code with the base64 command.But this command ...
1
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3answers
2k 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 ...
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0answers
28 views

Cannot use --cut-dirs nor -np in wget [closed]

I'm a Unix beginner and I tried to download sra files over ftp using these commands: wget -r -nH –-cut-dirs=8 ftp://ftp-trace.ncbi.nlm.nih.gov/sra/sra-instant/reads/ByStudy/sra/ERP/ERP007/ERP007205/ ...
3
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3answers
445 views

Including sub-parameters in help options to execute wisely without getopt or getopts?

I am writing a script which can choose a file and print specific content. For example, san#./script.sh Expected Usage : ./script.sh --file1 --dns (Here it checks for file1, search for dns name and ...
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4answers
1k views

Tail -f the most recent log file

In a few spots I got this to work ls -rt /path/to/log/file/ | tail -1 | xargs tail -f But I can't figure out why it won't always work (This is quick fix until I get the log rolling fixed here)
1
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1answer
41 views

shell script for date checking between two days

There is date in my file, like 30-apr-2015. How can I compare this with the current date and get notified if they are equal?
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votes
1answer
41 views

Replace mutiple strings with different values in a file using unix [duplicate]

I have a file in which the data is like below, 01,0000000,xxxxxxx/ 02,xxxxxxxx,yyyyyy/ 03,test1,41203016,,/ 01,0000000,xxxxxxx/ ...
3
votes
2answers
60 views

Why can't I load modules while executing my bash script, but only when sourcing it?

I am using modules to control the packages on my system and I have python/2.7.2 installed as a module. I have simple python executable python_exe.py which I am going to call from a simple 'driving' ...
1
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1answer
1k views

Deleting Non-empty Directory with smbclient

How can I remove a non-empty directory with smbclient? I have tried the following: 1) rm Result: NT_STATUS_NO_SUCH_FILE listing [dir_path] 2) recurse;rm Result: No Error but also nothing ...
0
votes
5answers
41 views

I want to design a scipt to send alert for Swap usage more than 85%

cat /proc/meminfo | grep Swap SwapCached: 460248 kB SwapTotal: 8388600 kB SwapFree: 1031900 kB I want to use this information to compare it with a threshold ...
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votes
0answers
15 views

print text portion from given string to given 1 string to send string

Lets have one example. cat fil1.txt cash memo mumbai item amount txn:45 good by cash memo mumbai item amoun txn:46 good by cash memo mumbai item amoun txn:47 good by basically its a txn ...
2
votes
4answers
195 views

How to 'drop' characters from in front of a string?

I have a string that I would like to manipulate. The string is H08W2345678 how would I be able to manipulate it so the output is just W2345678? Similarly if the I wanted to drop the last 4 ...
1
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1answer
39 views

Rsync Excludes Folders

I am running a rsync script and I want to exclude certain folders. I know with rsync you have to create a .txt file and add all the excludes in there but I am wondering is it possible to just have a ...
0
votes
1answer
59 views

grep: Syntax error near unexpected token `('

I have this problem: I'm looking for a string inside file . Syntax is: grep -E ‘( ^ | [[:space:]] )[A-Z]{2}[[:digit:]]{2}((- | [[:space:]] )[[:alnum:]]{4}) {3} ’ (filename) When I run this ...
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0answers
36 views

How to implement command history in Linux terminal?

I am using Putty as Terminal to connect a Linux server running Oracle Linux. To use a command multiple times, I have to type that command each time. There is no function of Up and Down button unlike ...
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1answer
33 views

What is the email matching regex in basic regex for grep?

I created a text file and put some email addresses in it. Then I used grep to find them. Indeed it worked: # pattern="^[a-zA-Z0-9]+@[a-zA-Z0-9]+\.[a-z]{2,}" # grep -E $pattern regexfile but only as ...
1
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2answers
85 views

Finding files that contain multiple strings

I am trying to find scripts that contain common malicious code, I need to match multiple strings within each file. What I am using is working but am not sure why I get the following in the output: # ...
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0answers
27 views

Can we connect Winscp using power broker?

I am connecting through power broker i.e pbrun command via putty to server. Can someone guide me, How can I connect to the server if I am using WinSCP because authentication will be done only I ...
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1answer
16k views

“not a valid identifier” when I do “export $PATH”

When I run export $PATH in bash, I get the error not a valid identifier. Why?
0
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2answers
37 views

Run script on non-full bash-login invoked as “sh”

Good day I'm currently trying to modify my terminal to have the prompt displayed in a different colour than the whole rest of the shell, and I would like to make it white for normal users and red for ...
0
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1answer
34 views

shell sleep until next full minute

To execute a script on the next full minute I want to tell the sleep command to sleep until the next full minute. How can I do this?