Commands tagged bash sorted by votes

Commands tagged bash (821)

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Change all xxx.png files' name to xxx@2x.png for iOS
This is sample output - yours may be different.
0

ls -1 | sed 's/$.*$\.$.*$/\"&\" \"\1@2x\.\2\"/' | xargs -n2 mv

dieface · 2015-08-05 20:24:16 9
Set Apache 2.4 log level on RHEL6

Uses sed to quickly set log level in httpd.conf. For Apache 2.4 installed via Software Collections on RHEL6 systems.
This is sample output - yours may be different.
0

loglevel() { sudo sed -Ei.bak "/LogLevel\s/s/alert|crit|debug|emerg|error|info|notice|warn/${1}/" /opt/rh/httpd24/root/etc/httpd/conf/httpd.conf }

jblackwood · 2015-08-13 22:14:40 9
Generate a directory path based on the date and time

Great for backup / restore scripts. May want to remove the %M/%S to group backups by hour. If using a script, set a variable earlier with the date command, then reference that variable. Otherwise, time will keep on rolling ;-) declare -rx script_start_time="$(date '+./%Y/%m/%d/%H/%M/%S')" mkdir -p "$script_start_time" Show Sample Output
This is sample output - yours may be different.
```
forest@murgatroyd:~/2015/11/21/00/39/56$ pwd
/home/forest/2015/11/21/00/39/56
```
0

mkdir -p "$(date '+./%Y/%m/%d/%H/%M/%S')"

forestb · 2015-09-25 08:56:26 11
use a command's output as arguments for another
This is sample output - yours may be different.
0

first_command | xargs other_command

lolssl · 2015-10-01 19:53:28 10
Download files linked in a RSS feed

Just added a little url encoding with sed - urls with spaces don't work well - this also works against instead of enclosure and adds a sample to show that you can filter against links at a certain domain Show Sample Output
This is sample output - yours may be different.
```
Reusing existing connection to www.yourfeed.com:80.
HTTP request sent, awaiting response... 200 OK
Length: 176975 (173K) [application/pdf]
Saving to: 'MyFile.pdf'

MyFile.pdf            100%[==================================================================================================================>] 172.83K   488KB/s   in 0.4s   

2015-10-30 15:06:24 (488 KB/s) - 'MyFile.pdf' saved [176975/176975]
```
0

wget -q -O- http://www.yourfeed.com/rss | grep -o "<link[ -~][^>]*" | grep -o "http://www.myfeed.com[ -~][^\"]*" | sed "s: :%20:g" | xargs wget -c

dermidgen · 2015-10-30 22:13:43 24
Print all 256 colors for testing TERM or for a quick reference

Basically, \033[ is a semi-portable unix escape character. It should work in linux, osx, bsd, etc. The first option is 38. This tells whatever is interpreting this (and this is merely convention) that a special color sequence follows. The next option is 5 which says that the next option will specify a color ? {0..256} of course. These options, as you can see, are separated by a single `;` and the entire escape sequence is followed by a mandatory `m`. The second escape sequence (following "COLOR") is simply to clear all terminal attributes (for our purposes, it clears color). This for loop is helpful for testing all 256 colors in a 256 console (note: this will not work in a standard Linux tty console) or to see which number corresponds to which color so that perhaps you can use it! Show Sample Output
This is sample output - yours may be different.
```
1 COLOR
2 COLOR
...
255 COLOR
256 COLOR
```
0

for i in {0..256}; do echo -e "${i} \033[38;05;${i}m COLOR \033[0m"; done

Benharper · 2015-12-17 23:49:42 12
Test remote SSH server status using telnet (no login required)

This command telnet and and looks for a line starting with "SSH" - works for OpenSSH since the SSH banner is something like "SSH-2.0-OpenSSH_6.0p1 Debian-4+deb7u3". Then it triggers an action accordingly. It can be packed as a script file to echo 0/1 indicating the SSH service availability: if [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]]; then echo 1; else echo 0; fi; Alternative uses: Trigger an action when server is UP (using &&): [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]] && <command when up> Trigger an action when server is DOWN (using ||): [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]] || <command when down>
This is sample output - yours may be different.
0

$if [[ "$(sleep 1 | telnet -c <host> <port> 2>&1 | grep '^SSH')" == SSH* ]]; then <command when up>; else <command when down>; fi;

paulera · 2016-02-02 13:06:51 16
Read curl output line by line in a while loop

This command will take the output of curl and read it line by line, skipping a step in downloading the file then parsing it. You can then parse each line, or only print the lines that contain certain works using if statements, or whatever you can come up with. Or you can change IFS and use it to parse based on separators other than newline.
This is sample output - yours may be different.
0

while read line; do echo $line;done < <(curl -s <URL of file to read>)

baize · 2016-02-05 17:04:15 18
enable all bash completions in gentoo

Pros: * it's much faster then for loop * removes first line of 'eselect bashcomp list' - which contains text "Available completions:"
This is sample output - yours may be different.
0

eselect bashcomp enable --global $(eselect bashcomp list | tail -n +2 | awk '{print $2}' |xargs)

eNcacz · 2016-02-12 16:53:22 12
Returns the current timestamp
This is sample output - yours may be different.
0

date +%s

hollandaisvolant · 2016-02-13 19:04:50 12
Reports file systems with disk usage exceeding 90% on the specified host
This is sample output - yours may be different.
0

function df_func { local dfts=$(ssh $1 "df -lP | tail -n +2 | sed 's/%//'"); echo $dfts | awk '$5 > 90 {exit 1}' > /dev/null; if [ $? == 1 ]; then echo -n "$1 "; echo $dfts | awk '$5 > 90 {printf "%s %d%%\n", $6, $5}'; fi }

wytten12 · 2016-03-30 19:57:39 10
Diff two directories by finding and comparing the md5 checksums of their contents.

As output, checksums and filenames will be printed.
This is sample output - yours may be different.
0

diff <(sort <(md5deep -r /directory/1/) | awk -F '/' '{print $1 $NF}') <(sort <(md5deep -r /directory/2/) | awk -F '/' '{print $1 $NF}')

linux_noob · 2016-06-06 20:05:01 11
Recursively remove all files in a CVS directory

This command is much faster than the alternatives, because it uses one cvs command to remove everything, instead of doing a separate cvs command for each individual file. The '-f' option removes the file from disk as well as from CVS. Note that those are backticks in the command (under the tilde key), not single quotes. Show Sample Output
This is sample output - yours may be different.
```
cvs remove: scheduling `./file1.txt' for removal
cvs remove: scheduling `./somedir/file2.txt' for removal
```
0

cvs remove -f `find . -type f ! -path \*CVS\*`

ssorley · 2016-07-13 17:45:05 13
better forkbomb (*DO NOT USE*)

Don't use. This defines a function `:` that will create two more of itself, infinitely in the background. While this function is itself defined in the background, it is run up in the front.
This is sample output - yours may be different.
0

:(){ :|:& }&:

tox123 · 2016-08-05 15:45:10 14
Diff two directories by finding and comparing the md5 checksums of their contents.

Results will be shown in columns. Only different files and files in one directory that is not in the other will be shown.
This is sample output - yours may be different.
0

diff -y --suppress-common-lines <(sort -k2 <(md5deep -r -b directory1)) <(sort -k2 <(md5deep -r -b directory2))

MeLoPasoPipa · 2016-08-18 09:17:16 12
See how many times you've typed 'ls' by itself

I seem to do this compulsively every time I change directories, sometimes even when I don't, even if I know exactly what I need to do. (Don't worry, the sample output is just an exaggeration. :) Show Sample Output
This is sample output - yours may be different.
```
23934729
```
0

grep -cx ls ~/.bash_history

Sparkette · 2016-09-14 17:06:59 17

Display the top ten running processes - sorted by memory usage

This command is better for just displaying the memory in KiB. Show Sample Output

ps -eo size,command --sort -size | head

bracourt · 2016-09-30 20:03:21 19

flush stdin in bash

Type the ^D by first typing a ^V. This makes the line delimiter be EOF, which makes read read everything up to EOF then exit.
This is sample output - yours may be different.
0

read -d ^D

cantorman · 2016-11-02 22:44:31 37
Pretty print docker ps command

If you have many port mappings, docker ps output becomes pretty illegible. The ~120 char one-liner changes the output into a more readable list of container! Show Sample Output
This is sample output - yours may be different.
```
$ docker ps [...]

70f949a68c3f               # bold
image:latest
"/start.sh"
8 hours ago
Up 8 hours                 # colorful if up or down
127.0.0.1:9002->9000/tcp
zauberstuhl                # underlined

[...]
```
0

docker ps | perl -ple "s/\$/\n\n/g;s/\s{2,}/\n/g;s/(Up)/\\e\[32m\$1\\e\[0m/g;s/(Down)/\\e\[31m\\e\[5m\$1\\e\[25m\\e\[0m/g;s/^([^\n]+)/\\e\[1m\$1\\e\[0m/g;s/(\w+?)$/\\e\[4m\$1\\e\[24m/g" | more

zauberstuhl · 2017-01-05 02:46:15 14
Check spelling of word using regex

Runs on at least MacOS Sierra (in Bash) Show Sample Output
This is sample output - yours may be different.
```
compatibility
```
0

egrep "^compat.bility$" /usr/share/dict/words

demonzrulaz · 2017-02-24 05:20:40 17
Execute md5sum and sha in the same files in a single command.

Stat -c %n #list files. A find command is also useful Tee #use stdout, but reseend to next comand. Can be other Tee ad infinitum xargs #use de name of files to execute md5 and sha diggest.
This is sample output - yours may be different.
0

stat -c %n * |tee >(xargs md5sum >estedir.md5) >(xargs sha512sum >estedir.sha)

Wallebot · 2017-02-27 18:43:28 15
Calculate xor in bash

This command calculates the XOR from two given HEX numbers ($1 and $2) Show Sample Output
This is sample output - yours may be different.
```
0-F
```
0

echo $(( 0x$1 ^ 0x$2 ))

imjoseangel · 2017-04-09 11:34:46 60
get a random command-line-fu tip

You can put this at .bashrc or .profile and get a random tip every time you open a terminal Show Sample Output
This is sample output - yours may be different.
```
# commandlinefu.com - questions/comments: tech@commandlinefu.com

# get a random command-line-fu tip
w3m -dump http://www.commandlinefu.com/commands/random/plaintext

# AD: Diff 2 entire servers at ScriptRock.com
```
0

w3m -dump http://www.commandlinefu.com/commands/random/plaintext

noobcodr · 2017-05-14 02:11:12 21
Download first mp3 file linked in a RSS feed
This is sample output - yours may be different.
0

wget `curl -s <podcast feed URL> | grep -o 'https*://[^"]*mp3' | head -1`

tbon3r · 2017-07-16 23:02:03 25
Create a directory and change into it at the same time
This is sample output - yours may be different.
0

take dirname

prabhakaran9397 · 2017-09-26 16:12:46 21
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Convert CSV to JSON

Replace 'csv_file.csv' with your filename.

Insert the last argument of the previous command

for example if you did a: $ ls -la /bin/ls then $ ls !$ is equivalent to doing a $ ls /bin/ls

Reboot as a different OS in Grub

This will reboot as the Grub 2 option.

Which processes are listening on a specific port (e.g. port 80)

swap out "80" for your port of interest. Can use port number or named ports e.g. "http"

Change to $HOME - zsh, bash4

To change to $HOME in that manner you need to set a shell option. In zsh it is auto_cd, hence $ setopt -o auto_cd in bash4 it is autocd, hence $ shopt -s autocd What the option does is allow you to cd to a directory by just entering its name. This also works if the directory name is stored in a variable: $ www=/var/www/lighttpd; $www sends you to /var/www/lighttpd. CAUTION: If a command or function name identical to the directory name exists it takes precedence.

grep for minus (-) sign

Use flag "--" to stop switch parsing

Type strait into a file from the terminal.

Takes input from the connected terminal and dumps it to the specified file. Stop writing and close file with control + D or the end of line character. Useful for copying+pasting large blobs of text over SSH to a new machine.

Create tar over SSH

Really useful when out of space in your current machine. You can ran this also with cat for example: $ tar zcvf - /folder/ | ssh root@192.168.0.1 "cat > /dest/folder/file.tar.gz" Or even run other command's: $ tcpdump | ssh root@10.0.0.1 "cat > /tmp/tcpdump.log"

Summary of disk usage, excluding other filesystems, summarised and sorted by size

This command is useful for finding out which directories below the current location use the most space. It is summarised by directory and excludes mounted filesystems. Finally it is sorted by size.

Tail postfix current maillog and grep for "criteria"

Tail curren postfix maillog.

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Commands tagged bash (821)

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