Questions about bash only, as opposed to other Bourne/POSIX shells. For all Bourne/POSIX-style shells, use the /shell tag instead.

learn more… | top users | synonyms

14
votes
7answers
40k views

bash - replace space with new line

How can I replace spaces with new lines on an input like: /path/to/file /path/to/file2 /path/to/file3 /path/to/file4 /path/to/file5 etc... To obtain the following: /path/to/file /path/to/file2 ...
7
votes
4answers
356 views

Prevent terminal from displaying previously executed command

I have a script that allows me to log random thoughts while working on a project. In the terminal I would add a new log entry by running $ @ "some random thought" where @ is just an alias for my ...
4
votes
2answers
5k views

Insert to oracle table in a loop

Requirement: In one server in a directory multiple files are present. I need to read the file names and populate into a oracle table. I have written the script like this, but its not working: ...
3
votes
2answers
8k views

Convert csv to HTML table

I have a Medical.csv file with rows of following format, field: 'participation.type', displayName: 'program_type', type: 'String',path:'participation' field: 'participation.program', ...
5
votes
3answers
171 views

how do I set quotes around a variable so that the programs sees them as quote marks

I am trying to get quotes around a variable to make is just like I typed it in the terminal to get this script to work. it shows " quotes around the varibale " but still does not see it as quotes, as ...
9
votes
4answers
825 views

Split the file and put it in corresponding data structure?

I have a file which contains the single line below: {machineA=[0, 1024, 4, 1028], machineB=[1, 1025, 5, 1029]} in which I have two datasets: machineA=[0, 1024, 4, 1028] machineB=[1, 1025, 5, 1029] ...
9
votes
2answers
2k views

How does GLOBIGNORE work?

According to bash's manual page: GLOBIGNORE A colon-separated list of patterns defining the set of filenames to be ignored by pathname expansion. If a filename matched by a ...
3
votes
1answer
274 views

Read the files in shell script doesn't print out anything?

I am trying to read a file from shell script line by line. Below is my file content - hello=world And below is my shell script that I have written - #!/bin/bash while read -r line; do ...
0
votes
1answer
2k views

Changing hostname doesn't change the terminal name

I had set my hostname while installing linux as "ankit". i want to change it to "ankit.centos". I tried changing hostname in /etc/hosts, /etc/sysconfig/network and sysctl kernel.hostname=ankit.centos. ...
-1
votes
2answers
11k views

Append variable string to itself [closed]

I have a variable into a do loop. I append its content to a file, but I want to append it to itself so I could use it to do other stuff like sending mail. I tried variable+=$variable but it didn't ...
0
votes
2answers
545 views

How to add the logs to a crontab with time stamp [duplicate]

In crontab, I scheduled a daily backup script. Now when the cron executes the script the status are logged to a log file as shown below. 0 0 * * * /home/backup.sh > ...
16
votes
2answers
1k views

Can the empty spaces/background in a terminal be replaced with a random(but pretty) pattern of ASCII characters?

Context and Question There are many ways to colorize the terminal and shell environment. The output of individual commands, such as ls and grep, can also be colorized. Not directly related but ...
4
votes
3answers
207 views

How to only output lines that are younger than 3 months?

cat a.txt 1387111124 ./asfjlasdf.txt 1348681215 ./akdfyxcv.txt So I need this: cat a.txt | SOMEMAGIC 1387111124 ./asfjlasdf.txt The output should only have the lines that are younger than 3 ...
6
votes
4answers
2k views

convert date format in log

I have a log with following date format: 2013-12-14 18:53:33 aaaaaaaaaaaaaaaa 2013-12-14 18:53:33 bbbbbbbbb 2013-12-14 18:53:33 ccccccccccccccccccccc What would be the simplest solution to convert ...
3
votes
1answer
703 views

How to switch tty with a script / cronjob

Is it possible to switch the current tty/vt with the help of a bash script or a cronjob? I only know the physical keyboard input "Ctrl-Alt-Fx". I would like to show two virtual desktops at different ...
2
votes
5answers
105 views

using regex with find

Let's say I need to find all files in /var/log/ except btmp, lastlog, wtmp. And I only need depth 1. I tried with the following find command, but that does not work as expected: find /var/log/ ...
3
votes
2answers
455 views

Bash if script is called from terminal echo stdout to terminal, if from cron do not echo output

I would like to have a service watchdog script echo the status to the screen if called like ./watchdog.sh but if it is run by cron, there is no need to echo output. What is the proper method? Where ...
4
votes
2answers
176 views

Bash Syntax Colouring

I tried the fish shell, and love the fact that it does syntax colouring in the shell itself: Is there some way to do this in bash?
3
votes
4answers
4k views

Searching a pattern in file names with number

I have a large number of files in a folder each with the date as the filename. For example 20130101 20130102 20130103 . . . 20130131 similarly for other months 20130201 to 20130230, the pattern is ...
0
votes
1answer
710 views

bash log in windows and run cmd command using .sh script?

Ip of my Windows machine is 172.16.22.53, and it installed cygwin. I want write a bash script like that: #!/bin/bash sshpass -p 'myPassWord' ssh userNmae@172.16.22.53 #and some command to run cmd ...
8
votes
2answers
3k views

Removing non printable characters from expect logs?

How can I either strip the following character sequences from my files? ^[[64;8H, ^[[?25h, ^[[1;64r etc or avoid having expect add them in the first place? Background: I'm using a collection of ...
17
votes
3answers
58k views

remove particular characters from a variable using bash

I want to parse a variable (in my case it's development kit version) to make it dot(.) free. If version='2.3.3', desired output is 233. I tried as below, but it requires . to be replaced with another ...
6
votes
4answers
5k views

Intersection of two arrays in BASH

I have two arrays like this: A=(vol-175a3b54 vol-382c477b vol-8c027acf vol-93d6fed0 vol-71600106 vol-79f7970e vol-e3d6a894 vol-d9d6a8ae vol-8dbbc2fa vol-98c2bbef vol-ae7ed9e3 vol-5540e618 ...
1
vote
2answers
87 views

How to run bash on CYGWIN

I have created following file with name test.sh #!/bin/bash name = "Elvin John Paul" echo $name echo ${name#* } echo ${name##* } echo ${name% *} echo ${name%% *} and I am getting some error as ...
3
votes
2answers
1k views

Passing options to subcommands in bash

I'm scripting a sequence of commands I used to enter by hand. The rough outline goes something like this $ echo ${FILENAME_ARGS} | some | big | pipeline | sort -options | etc >temp $ gs ...
15
votes
3answers
2k views

How can I create a local function in my bashrc?

My .bashrc had some code that was repetitive so I used a function to simplify it do_stuff() { local version=$1 export FOO_${version}_X="17" export FOO_${version}_Y="42" } do_stuff '5.1' ...
2
votes
1answer
115 views

“No such file” warning on terminal launch

I ran a source command on a file that was missing. I forgot about it but later noticed that every time I opened a new terminal, the first line would be a warning about the missing file bash: ...
0
votes
1answer
10k views

How to reassign new values to array elements?

I'm trying to figure out like three or four things at the same time.The most I need help with is how to get the greatest number in all the files that I have created on a prior run of my script, that ...
4
votes
3answers
476 views

Bash: handling “[[ statement ]] || echo problem found ; exit 1” logic

In the statement in the title, there is a problem that even if the statement is true, it will still exit with status 1 because, as I understand it: [[ statement ]] || echo problem found ; exit 1 ...
-1
votes
2answers
60 views

is there a proper syntax for the expression or is this impossible [closed]

STD_IN=&1 data=<( read data from $STD_IN ; echo $data; ) echo $data Target: Is to get a blocking read into the subshell like this
1
vote
2answers
134 views

Removing “[crap-like-this]” from strings using bash parameter expansion?

If I have the following $STRING aaa.bbb.ccc.[ddd].eee.fff.[ggg].hhh is there any way, using bash parameter expansion, to echo the following aaa.bbb..ccc.eee.fff..hhh That is, remove all ...
1
vote
2answers
133 views

Command working from CLI but not from script

I have a command that I use from the CLI to properly color files, folders, executables, etc. The command that I'm executing looks like this: test -r ~/.dircolors && eval "$(dircolors -b ...
3
votes
1answer
7k views

Screen in bash script

I am using a bash script and I need to create a screen, execute a specific command with a memory limit and detach the screen. I have been trying something similar: #!/bin/bash for i in 1 2 3 4 5 6 7 ...
7
votes
2answers
1k views

Re-execute fc command from history

Sometimes I am using the fc builtin in bash (3.2 if that matters), to recall commands from the history. This also offers the possibility to edit, before execution. For example, by typing fc 23 27 ...
0
votes
1answer
113 views

Could not get a command to work with bash -c

I am trying to execute a command to find out which process is listening on a particular port and i cannot get it to work if the command is passed as an argument to bash using bash -c netstat -tnlp ...
25
votes
3answers
2k views

Multicolored Grep

I'm trying to get each grep command to highlight it's results in a different color. I can do it manually with a line like this: ls -l GREP_COLORS='mt=01;32' grep c | GREP_COLORS='mt=01;31' grep o | ...
8
votes
2answers
283 views

Re-installing apps after a fresh install?

I'm on Debian and I want to re-partition my drive and reinstall. Is there an easy way to restore all currently installed packages after a fresh installation? I'm thinking of doing it by making a ...
3
votes
2answers
3k views

Remove scientific notation bash script

When I convert MB to GB I'm getting below output. I want this output in normal format. When I use bc I'm getting an error. The text file contains nearly 100 such lines like this. I want to print this ...
4
votes
3answers
3k views

How can I recall a numbered history command for edit?

I frequently search for changes with history | grep 'string' I get a list of commands in my history, along with the history line number), e.g. history | grep 'git' 755 git status 1535 git push ...
2
votes
2answers
103 views

Changing username still leaves old traces

I changed my username about a month ago, and although I have forgotten the specificities of how I had done so, I'm pretty sure I followed the instructions on the Arch Wiki. Since then, some programs, ...
1
vote
4answers
3k views

How do I delete files with spaces in them in bash script?

this is a three part topic to a two part process that still is not working for me: Objective: to manipulate a filename then delete it the filename has spaces between the words then the dot .ext ...
0
votes
2answers
92 views

What's the difference of get command output using`command`and $(command) in Shell? [duplicate]

What is the difference in collect a command output in Shell script using `command` and $(command)? For example: # IP1=$(ifconfig eth0 | grep -e "inet " | cut -d: -f2 | awk '{print $1}') # ...
7
votes
3answers
269 views

In shell config scripts, how can I account for differences between coreutils on BSD compared to GNU?

Up until this month, my shell configs have been pretty simple (just a .bashrc or .bash_profile with some aliases mainly), but I have been refactoring it so I can get different behavior depending on ...
19
votes
2answers
4k views

Is there any way to enable Ctrl+L to clear screen when 'set -o vi' is set?

When you press Ctrl+L in bash default mode the screen is cleared. But when I run set -o vi and press Ctrl+L the keystroke is printed (^L). Is there any way to keep this behavior?
3
votes
1answer
468 views

bash set env variable is not working in pdsh

I am using PDSH to control multiple servers through one command line. The command below works fine on individual servers, but when I enter the export command within PDSH, echoing it back is empty. ...
0
votes
2answers
475 views

bash script, printing multiple lines that matching to a specific patern

I have a log file and I'm making a script to do some actions. An action is to print a specific area of the log. Every block at the log starts with a specific time stamp and inside the block may have ...
7
votes
1answer
6k views

Set dynamic window title based on command input [duplicate]

I am looking for a way to dynamically set the urxvt window title based on the command input. Let's take an example. If I run mplayer http://66.197.229.245:8082 in an urxvt window, I would like the ...
5
votes
1answer
2k views

How do I tell if a program is printing to stderr or stdout in the terminal?

NOTE: a newline appears but od -c doesn't display it. My music player's status command (quodlibet --status | od -c) has three states, and I'm trying to write a conditional based on that output. The ...
6
votes
1answer
115 views

Meaning of “:-” in bash [duplicate]

I have a bash code export TM_SCALAC=${TM_SCALAC:-scalac}. I'm not sure the meaning of ":-" inside the ${}. How do I interpret this line of bash code?
6
votes
5answers
22k views

Parsing a delimited text file in bash as command arguments

I have a text file split up like so: field1,field2,field3 xield1,xield2,xield3 dield1,dield2,dield3 gield1,gield2,gield3 Each of these columns will be a parameter to a program, and I would like ...