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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see newest release last (YML release files with the same timestamp from Git)

I pull from Git *yml files with "$packagename-$release.yml". The highest number is the most recent release. I wish to have the listening with latest release last. Correct sort order ...
1
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3answers
131 views

Using AWK to convert numbers to 0 or 1

This might be a simple question but I can't figure it out for the life of me. I have a file called keyout.dat which looks like this: Title 1 Variable -999 -999 0.234 0.123 -999 -999 0.555 The file ...
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2answers
43 views

Can't get if statement to run correctly. Beginner. [duplicate]

I am very new to bash, just playing around in my free time off work. I want to check if a file exists, and if it doesn't exists, I want to ask the user if they'd like to create it. Whether the user ...
0
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1answer
44 views

tar exclude files *.zip

Why don't *.zip patterns work in tar : tar cfjv backup.tar.bz2 --exclude mydir/files/*.zip mydir Is there another syntax?
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0answers
51 views

$PATH variable on Fish Shell OS X

I have somehow screwed up my path variables with Fish shell on OS X. Is this the proper $PATH variable in the config.fish? user@host ~> more ~/.config/fish/config.fish set -g -x PATH ...
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0answers
61 views

Easy way to compare BIOS information between two machines?

I have two machines - machineA and machineB running Ubuntu 12.04 Is there any easy way I can compare BIOS settings between those two machine and see the difference instead of doing it manually using ...
2
votes
3answers
110 views

find directories with specific patterns leads to Permission denied error and no result

I have this kind of shell script on Linux: #!/bin/sh echo -n "Please enter directory pattern: " read dirs find $dirs > /tmp/justbay.txt allDirs=$(find $dirs ! -readable -prune) echo $allDirs ...
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2answers
85 views

works as a command but not as a shell script. Why?

$ grep "apple" fruits.txt apple $ if [ $? == 0 ] ; then echo "A"; else echo "B"; fi A When I execute the above commands it works fine but when I run these commands as a shell script it throws error ...
3
votes
4answers
50 views

find on a set of dirs that may not exist

I need to invoke find on a set of "starting points" which is generated, but some of paths may not be valid: paths() { # # mock version of the generator # echo /bin echo kjsdfhk ...
2
votes
2answers
145 views

bash: can't set a variable to a solid string [duplicate]

I cannot set a variable with a whole command-string as following: A="/bin/ps wwwaux" for a in $A do echo "$a" done It assigns array instead of solid string somewhy. Could you assist, please. My ...
2
votes
2answers
36 views

sed replace after matching character

I have to change a properties file containing the property: ro.product.firmware=0.0.1 with a new value that is coming from a function called in a different section of my bash script. I cannot get ...
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votes
4answers
69 views

How to track/log commands executed on a shell?

Can commands be written to a logfile before they were executed in any shells? I know there is a patch for ssh to log all commands from ssh sessions, but i want to log even commands executed from a ...
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2answers
35 views

sed replace ;“ content with ';”

I have files that contain ;" and I need it replaced with ';" The following sed command does not work: sed -i "s/;"/';"/g" /root/bashy.sh How can I do this? The solution doesn't have to be sed.
1
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1answer
26 views

makefile fails when deleting a file [closed]

I am trying to write makefile and check - if a folder exist - delete it : BINUTILS_TAR_GZ := binutils-2.25.tar.gz BINUTILS_ORIG := binutils-2.25 BINUTILS_CHANGES := binutils_changes . . . clean: ...
2
votes
1answer
69 views

Get all filenames in a directory created before input date

I have a directory containing lots of files. The output of ls command is -rw-r--r-- 1 nobody nogroup 427494 May 26 13:59 14_20150526065238928590_102.txt -rw-r--r-- 1 nobody nogroup 2113592 May ...
7
votes
2answers
349 views

Why does xargs skip first argument when passing to subshell?

Looking for a way to invoke more than one command in a xargs one-liner, I found the recommendation in findutils to invoke the shell from xargs like this: $ find ... | xargs sh -c 'command $@' The ...
3
votes
3answers
81 views

How can I count the number of times a phrase appears in a file, and format it neatly?

I have a log file I am trying to pull data from. It is formatted like so, and lists when certain modules are checked in and out: 19:50:26 (license_manager) OUT: "certain_module" doej@server.domain ...
1
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1answer
39 views

Why does bash try to execute strings in a string substitution?

My script is supposed to take input from a pipe and replace newline characters with commas, using the bash's string substitution: #! /bin/bash read -d -r input echo $input $input=${input//\n/,} ...
3
votes
3answers
69 views

Copying a Parent Directory into a Subdirectory Without an Infinite Loop

For application specific reasons, I need to copy an entire parent directory into a subdirectory. E.g., cp -r ../ tmp/ The problem with this is that it gets stuck in an infinite loop, recursively ...
2
votes
2answers
42 views

Extra space with counted line number?

I count the number of lines of my file with this command on OSX: nl=$(wc -l < ~/myfile.txt) Say, nl turns out to be 100. Now, I wish to use the result nl in another command, but weirdly, echo ...
1
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2answers
36 views

Shell script exit code and logging

I have got following simple shell script, in which I am trying to send STDERR & STDOUT to both screen and log it in a file(test.log). Also, while exiting I am trying to exit with appropriate exit ...
2
votes
2answers
61 views

What allows a command to be typed while the previous command is still running in foreground?

Sometimes I have seen when one program (say A) is running in the foreground and printing its output to stdout, I can type another command (say B), and when I press Enter it is run, even though I had ...
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votes
1answer
45 views

Move folder from root of Hard Disk to Current Directory [closed]

I'm trying to figure out how to move a folder that sits in the root of my disk (what do you call that, home?) to a subdirectory. I am not cd'd to the root (again not sure of the terminology). When I ...
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0answers
59 views

Run Git Pull from a shell start-up script

I have raspberry-pi that loads a shell script on start up. This script runs a python script 'boot_camera.py' which is found in a repository. I Have a server which sends the raspberry-pi a command ...
0
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1answer
27 views

Checking the schedule of a cronjob and doing a conditional check on specific parts

Edit: I managed to solve this myself, I actually deleted my original question as I was over complicating the process slightly, but have since answered it in case others find it useful. RegExp is not ...
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3answers
56 views

Find a file with the extension .csv in a directory matching a pattern

I have a folder in which I have many subfolders. The Root folder name is allCSV and sub foldername is will be like a_date(s), b_date(s), c_date(s) ... I want a file which is in a_date(s) and ends ...
4
votes
4answers
361 views

grep command not working in conditional statement

I've a bash script that's supposed to go over all the filenames and print them only those that contain a certain letter (let's say it's 'o'). What I've done: command=`ls -l` for file in $command do ...
1
vote
1answer
125 views

How can I combine information of three files to create a fourth one?

I have three csv files, each of them containing the information I need to get a fourth one. I'm describing toy files but the actual ones contain much more columns and rows, still on the same models. ...
4
votes
4answers
211 views

Move files by date into different directory using CLI

I have a large number of pictures from an old hard drive that I'm trying to organize. If I run ls -l, I notice all of these files have a creation date of 2012 or before. Ideally, I'd like to move ...
1
vote
1answer
34 views

Aliasing a command with special parameters [duplicate]

I would like to have an alias for the following code:- g++ *.cc -o * `pkg-config gtkmm-3.0 --cflags --libs`; but I want that when I enter the alias it should be followed by the file name *.cc and ...
0
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3answers
95 views

Concat 1000 files within a directory [closed]

I know we can concat files by cat file [file] [[file] ...] > joined-file. I have directory which contains lots of files. I want to concat all of them. I want to concat 1000 files irrespective of ...
1
vote
1answer
85 views

Which one works faster - regular operators (such as <,>,=) or using (-lt, -gt, -eq)? and why?

Which one works faster - regular operators (such as <,>,=) or using (-lt, -gt, -eq)? and why?
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votes
4answers
141 views

How to show only the last k columns in ls -l?

I like to restrict the columns shown in ls -l command, by eliminating the first 4 columns. ls -lh shows: drwxr-sr-x 20 gamma alpha 4.0K May 22 13:18 Desktop drwxr-sr-x 3 gamma alpha 22 Oct 6 ...
-1
votes
2answers
55 views

Error in file comparison - awk [duplicate]

I have two files file1.txt, file2.txt. I want to select records which are common to both file1.txt and file2.txtbased on column 2 and column 3 and copy them to out.txt with additional column(column 4 ...
5
votes
1answer
98 views

Bash Script — ffmpeg not being invoked as expected

I'm working on a bash script to convert my music library to ogg* but executing the right command is somehow eluding me. This is the line that should accomplish it: ffmpeg -i "${file}" -f flac pipe:1 ...
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2answers
67 views

Copy .txt files in a certain directory

I have an issue in copying my file in my directories. I have .txt and .jpeg files in a lot of directories, and I want to copy only the .txt files according to the directory. For example, I have this: ...
3
votes
2answers
116 views

When should one use $( ) in defining variables

Some shell scripts I have come across use the following syntax when defining variables: file_list_1=$(echo "list.txt") or file_list_2=$(find ./) I would have used: file_list_1="list.txt" and ...
2
votes
1answer
29 views

What is a “checksum” and how do I use it from the shell?

I've seen on a lot of sites "checksum" hashes to verify the integrity of downloaded files. What are them and how do I use them? Ex: I have a downloaded-file.tar on the current working directory and ...
1
vote
1answer
46 views

Url Decoding shell script

How can I store the url-decoded string in a variable using shell script #!/bin/sh alias urldecode='python -c "import sys, urllib as ul;print ul.unquote_plus(sys.argv[1])"' ...
1
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0answers
25 views

Is it possible to create aliases that affect services starting?

Currently I have a custom service that executes java in multiple places. I want to be able to add an option to any executions of java this service will spawn (I'm specifying the error log location, ...
7
votes
2answers
134 views

Keeping history per working directory (cf. per shell session)

Is there a way to make a modern shell's history feature be scoped to a path? My working contexts are split up as paths on the file system, and the pattern of shell activity, such as repeatedly issued ...
10
votes
1answer
156 views

Why is nullglob not default?

In most shells nullglob isn't the default. That means, for example, if you run this command ls * in an empty directory, it will expand the *-glob to a literal ' * ', instead to an empty list of ...
2
votes
1answer
101 views

Return code for curl used in a command substitution

I've script as below :- (edited) httpUrl="http://www.nnin.com" rep=$(curl -v -X POST -d "UID=username&PWD=pass" $httpUrl) status=$? if [ "$?" -eq 0 ]; then echo "Success" exit $status ...
6
votes
2answers
281 views

How can I end a here-document that starts with <<\\$fff?

I was asked the following question in a test on shell scripting at my university, which never gave an answer, and google is of little help. Q: What is the line separator that should be used to end ...
14
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3answers
427 views

Prepare answers for questions of a command

Let's say I want to write a shell script that executes just one command. But this command is poorly designed. It doesn't offer any command line options; instead it asks some questions and waits for ...
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0answers
57 views

Shell Script to change user shell

I am writing a script that would be invoked to change user shell. The basic requirement is that once user gets authenticated (e.g: thorough some web application) the script would be invoked to set the ...
0
votes
1answer
23 views

FDs more than 2, more than (stdin/stdout/sterr)

I think this post is not off-topic.We had three traditional file descriptors in Unix contexts: 0 == STDIN 1 == STDOUT 2 == STDERR But in new articles, blogs, posts, answers, or so on, I read more ...
1
vote
2answers
59 views

Compare three files: lines present in one, but not in the other using column comparison

I have three files file1.txt, file2.txt, file3.txt and they are of same format(same number of columns with same data type). I want to select records from file1.txt which are not present in file2.txt, ...
1
vote
2answers
48 views

Accessing fish functions from perl

In bash I can do: foo() { echo bar; } export -f foo perl -e 'system "bash -c foo"' I can also access the function definition: perl -e 'print "foo".$ENV{"BASH_FUNC_foo%%"}' How do I do the same ...
0
votes
1answer
26 views

Percent Signs for Shell Vars to Remove Extension [duplicate]

for file in *.pdf ; do newname=${file%\\.\*} done I don't understand how the %\.* is removing the file extension, can someone walk me through it.