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, …).

learn more… | top users | synonyms (1)

3
votes
2answers
780 views

Remove slashes/parent paths from filenames inside CSS and Javascript content

I need to go through all my css and js files and if there is a filename referenced that has any slashes (/) at all then the slash should be removed. What I want is: if any files referenced are ...
2
votes
1answer
2k views

Enable line breaks when assigning multi line outputs to var in bash

I'm using the following very basic shell script I copied off the net to list the contents of my database backup folder and mail them regularly: MYSQLLIST=$(ls -lhG /var/backups/mysql/daily/) ...
2
votes
2answers
58 views

find closest matching folder

What is the best way to sort the results of $ find . -name scripts -type d by the occurrences of '/' and then choose the first result. I want to create a function that would cd down to a common ...
1
vote
1answer
40 views

Get value of environment variable in for loop

I have several environment variable pam_branch app_branch worker_branch I use an array to define different projects and I want to get the values of these env var by rebuilding them in a for loop ...
1
vote
1answer
94 views

Execute sh with parameters in bash

Hello I am newbie in bash and I am coding a daemon to execute a service. The syntax is ./ctlscript.sh start. When I execute service openproject start it should run this command, but it runs ...
1
vote
2answers
151 views

Get a refreshing list of running specific processes

I want to monitor running python processes with VSZ, RSS %MEM, %CPU etc. One of my priorities is a list refreshing every X seconds. I managed to come to the point of obtaining a refreshing list of ...
20
votes
11answers
3k views

Linux - command to list files (except ls)

Imagine you were working on a system and someone accidentally deleted the ls command (/bin/ls). How could you get a list of the files in the current directory? Try it. I tried many ...
0
votes
1answer
13 views

Convert Asyncronus reset into syncronus reset in verilog

I have multiple Verilog RTL files in which we have use asynchronous reset. But I want to convert asyncronus reset to synchronous reset. Before: always @ (posedge clock or negedge reset) After: ...
10
votes
3answers
737 views

Why does the “she-bang” begin with a “#!”?

Why does the "she-bang" begin with a #!, like #!/bin/bash? I have always accepted that this how it is done, but is there a reason behind it? Why start with #; isn't that usually a comment? Or is it ...
1
vote
2answers
38 views

Escaping double quotes in string

I have a string message which contains data in double quotes. I need to put \ in front of every double quote how can u do it in shell ? I used Perl and it works fine, but I'm looking for sh command: ...
5
votes
2answers
179 views

How to send all output to `logger` in POSIX shell?

I'd like to log standard output and standard error separately in .xprofile using logger. In Bash I think that would look something like this: exec 1> >(logger --priority user.notice --tag ...
5
votes
1answer
71 views

Variables outside of while loop

I am trying to echo the variables $f1, $f2, etcetera, outside of the while loop shown below. From what I understand, the scope of the variable is not correct. Therefore I tried a few of the ...
8
votes
7answers
2k views

How can I make a script to count up by fives?

I was trying to make a very simple bash script to list all of the multiples of five between 375 and 3500 (375, 380, 385...). One thing that I tried and didn't work is: for i in {375..3500} do ...
2
votes
3answers
84 views

Modify multiple files in different folders with one command?

I have a file abc.txt in the folder /etc/zyz/ and also in a few sub folders /etc/zyz-1/ /etc/zyz-2/ How can I modify all of those files with a echo command for example (all named abc.txt) in every ...
1
vote
1answer
30 views

Filesize in for loop

I am trying to get the filesize of each file in a folder by using stat in a for loop. I know why the following is going wrong, but I don't have enough knowledge yet on how to fix this. #!/bin/bash ...
1
vote
2answers
38 views

Piping contents of multiple files between programs while keeping contents separate

I would like to read in a number of files and pipe their output to subsequent programs while still maintaining them as individual pipelines of data. program1 *.txt | program2 | program3 folder I ...
0
votes
1answer
51 views

Why is my CD command not working on a home-built shell? [duplicate]

I have written a very basic shell in C. It reads the input, then runs it using system(lineCopy); (lineCopy being a copy of the input). All commands will run fine in it, other than cd. When I try to cd ...
0
votes
1answer
3k views

Proper escaping of double quotations for curl post data?

I'm trying to test out a server, by sending it JSON data and reading the response. I need to POST data like {"item":"value with spaces"} but when I use curl I find that it sends the backslashes as ...
106
votes
15answers
150k views

Colorizing your terminal and shell environment?

I spend most of my time working in Unix environments and using terminal emulators. I try to use color on the command line, because color makes the output more useful and intuitive. What options exist ...
1
vote
1answer
59 views

How to echo makefile variable through Make's $(shell …)

I have a GNU makefile. The makefile has a few tests (around line 65 from the linked file): UNAME = uname MACHINE ?= $(shell $(UNAME) -m) SYSTEM ?= $(shell $(UNAME) -s) IS_X86 = $(shell echo ...
0
votes
1answer
44 views

Which are (bash) shell special parameters?

I've found some special parameter with bash starting with $ sign. Example: When I was wandering for exit status I knew about $?, process ID by $$ etc. So, I am sharing this post to know Which are ...
0
votes
0answers
35 views

Why won't MOTD display output from a Python script it calls outside of /etc/update-motd.d/ unless it's in this directory?

The Situation We're running a headless Ubuntu 14.10 Server to fulfill various needs and tests. I was experimenting with changing the MOTD for SSH sessions via /etc/update-motd.d/ so as to display ...
-1
votes
2answers
116 views

Free or cheap shell (i.e., platform) to run a Linux C program with root privileges (raw socket)

I'm working on a Linux C program that needs root privileges (raw socket). I would like to run it on a host located in the US (I am in EU) to compare results. Is there any free (or cheap) shell ...
0
votes
1answer
50 views

Why the number is rounded over ssh? [duplicate]

localhost:~ $ df -k / | awk '{print $3/1024/1024/1024}' 0 0.00618061 localhost:~ $ ssh localhost "df -k / | awk '{print $3/1024/1024/1024}'" 01 01
2
votes
0answers
45 views

shell operation within makefile [closed]

I have the following line in my makefile: var := $(sort $(foreach m,$(libs),$($(m)-objs))) which I change in a way it now use sort from shell: var := $(shell echo $(foreach ...
36
votes
4answers
94k views

How to add repository from shell in Debian?

In Ubuntu one can add a repository to apt-get via the following command - sudo add-apt-repository ppa:yannubuntu/boot-repair As Ubuntu is based on Debian code base, I was expecting that the same ...
1
vote
2answers
50 views

Returning an variable from a function

I have the Linux script from bellow. I can get to return from the method decrypt nothing in order to unzip a file. The method decrypt sends a string with the name of a zip file. Please give some ...
2
votes
2answers
50 views

Call a script for another script, but don't exit the parent if the child calls exit

first.sh: #! /bin/ksh echo "prova" . ./second.sh echo "ho lanciato il secondo" . ./third.sh echo "ho lanciato il terzo" second.sh: echo "sono nel secondo script" dosomething1 exit $? If ...
0
votes
1answer
23 views

Run .zshrc when passing command via -c

I have a script that runs a command via zsh -c. However, when zsh runs, it doesn't appear to load ~/.zshrc. I understand a login shell flag exists, but even zsh -lc <command> doesn't seem to ...
1
vote
1answer
44 views

du reports directory size as much bigger than the sum of its contents

Running du -shc * in the top directory gives 110G for a particular folder, whereas running the same command inside that folder gives a total size of 11G. How is that possible? Platform Details: OS: ...
2
votes
1answer
39 views

bash on command event (or shell)

Is there a way to capture all commands executed in a bash or even better in sh? I need a wrapper script that gets called everytime a command is executed. Like when I type cd /home/ I want my ...
45
votes
4answers
7k views

How to use `which` on an aliased command?

Like most users, I have a bunch of aliases set up to give a default set of flags for frequently used programs. For instance, alias vim='vim -X' alias grep='grep -E' alias ls='ls -G' The problem is ...
2
votes
1answer
45 views

Restart bash from terminal without restarting the terminal application (mac)?

I've looked around and bit for an answer to this question but I don't seem to find it (which is weird). My question is, is there any simple way to restart the bash session from within the terminal on ...
-1
votes
2answers
96 views

shell script not running using crontab

This is my script mboxutil -l > n.txt sed 's/^.*user//' n.txt > n1.txt cat n1.txt | sed 's/^.//' > n2.txt sed 's/\/.*//' n2.txt > dss_list.txt rm -f n.txt rm -f n1.txt rm -f n2.txt sed ...
19
votes
15answers
1k views

How to find line with least characters

I am writing a shell script, using any general UNIX commands. I have to retrieve the line that has the least characters (whitespace included). There can be up to around 20 lines. I know I can use ...
0
votes
5answers
4k views

how to use & for sudo

I know if I put & at the end of application at the terminal, it will run in the background and terminal still can receive commands, for example: howchen@host:~ -> cutecom& [1] 17269 ...
1
vote
3answers
61 views

Pipe output of one command to two others [duplicate]

I need to pipe the output of one command to two other commands. cat filename.txt | tail -n 1 cat filename.txt | wc -l Since the file is huge I want to avoid reading it twice. I checked tee command ...
0
votes
2answers
66 views

cut string on last delimiter

I have a filename like a.b.c.txt, I want this string to be splitted as string1=a.b.c string2=txt Basically I want to split filename and its extension.I used cut but it splits as a,b,c and txt. I ...
2
votes
1answer
90 views

What are the Linux shells that allow network traffic management (sending/receiving data to/from `/dev/tcp/host/port`) via redirectors?

Following this Bash tutorial, I have succeded in obtaining the code of a web page issuing simple commands by using this method: $ exec 3<>/dev/tcp/www.google.com/80 $ echo -e "GET / ...
20
votes
5answers
6k views

How can I create an alias for a git [action] command (which includes spaces)?

Most of my my aliases are of this form: alias p='pwd' I want to alias git commit so that it does git commit -v But trying to create an alias with a space gives an error: $ alias 'git commit'='git ...
-9
votes
1answer
74 views

replace the the first line of all .sh files in a folder

Create list of all .sh files in current folder. Check first line of each file in this list and if file starts with #!/bin/sh then replace that with #!/bin/bash. Only modify files that have #!/bin/sh, ...
-5
votes
1answer
68 views

Find the number of files with sizes

Find the number of files with sizes > 100KB in /, /bin, /usr, /usr/bin and /usr/sbin directories and output them in a two column format with the name of the directory and the number of files.
0
votes
1answer
56 views

Bash script strange behavior - script does not act as manual commands

So, this is strange. When I manually run commands it all works fine, but when I run a script with identical commands, I get strange error output. This is what I run: lxc list; for elem in ...
-1
votes
1answer
56 views

How to rename or delete an alias permanently from system?

I have created one alias in my system, printf "%s\n" "alias shh='sqlplus hfdora/hfdora@hfd2" >> ~/.kshrc Now, I want to change the alias name from shh2 to shh Also, how to delete other ...
5
votes
2answers
3k views

xargs : using same argument in multiple commands

Am trying to write a one-liner that can probe the output of df -h and alert when one of the partitions is out [or almost] of space. It's the part using xargs that kicking me in the ass now... echo 95 ...
0
votes
0answers
19 views

Adapt text lines to fixed length [duplicate]

With the shell command fmt -w 30 myfile it is possible to truncate the myfile lines so that their length is at most 30 characters. The result is however not a justified file: some lines will be ...
9
votes
7answers
7k views

How to insert the content of a file into another file before a pattern (marker)?

File1 contents: line1-file1 "1" line2-file1 "2" line3-file1 "3" line4-file1 "4" File2 contents: line1-file2 "25" line2-file2 "24" Pointer-file2 "23" ...
0
votes
6answers
351 views

sed to replace with backspace

I have trail.txt, which contains spice netlist. Now I want to replace all expanded parameters to one line only i.e. remove + and append that line to previous line. trail.txt data + net06706 ...
0
votes
1answer
27 views

remove _ as prefix from the multiple files in a directory in Soalris [duplicate]

I have to remove _ which is as prefix for a file. I used: for i in _*.txt; do mv ${i} ${i/#_/''}; done but it does not change the names of the files which has space in between as _abc xyz-abc.txt ...
1
vote
1answer
43 views

Installed PDFInfo with Homebrew Cask but no command associated with “pdfinfo”

First, please excuse this very basic question. I'm sorry I have to ask it, but it's very difficult to find your way around the shell at the beginning. I installed pdfinfo with Homebrew Cask: brew ...