This pages contains a selection of tips for Linux (and UNIX) that I have collected. It's more of a memo to myself and not intended as a guide or anything. So just see it as notes that I share with whoever is interested. Most of these tips are for the bash shell environment.
replace "str1" by "str2" in previous command
^str1^str2[^]
repeat event from 2 events ago
!-2
repeat most recent event starting with "string"
!string
repeat most recent event containing "string"
!?string[?]
repeat the entire command line typed so far
!#
Directory listing including non-printable chars
ls -q *
list directory names not their contents
ls -d *
List all entries in current directory that are files (not directories),
alternatively use find with the -depth option.
for i in *; do [ -f $i ] && echo $i; done
And inversely list only directories:
for i in *; do [ -d $i ] && echo $i; done
Push current directory to directory stack:
pushd .
Pop directory from directory stack:
popd
Information about the system:
uname -a
Run one instruction as user id:
su - id -c "instruction"
Mail a file as plain text:
mail -s "subject" e-mail_address < file
Mail an attachement (if uuencode present and in path):
uuencode attachment.txt | mail -s "subject" e-mail_address
Do some quick maths:
echo $((7*8+5))
Display current processes
ps -ef|cut -c49-
Display the processes of user userid
ps -fu userid
Show the processes started on tty
ps -ft tty
Show the process with PID pid
ps -fp pid
Restarting a process with PID pid:
kill -HUP pid
Restarting sshd:
kill -s HUP $(cat /var/run/sshd.pid)
Editing ssh settings:
vi /etc/ssh/sshd_config
Changing (lowering) a running process' priority:
renice +10 -p pid
Commands you can use in an FTP session:
site mask 133 site chmod 644 filename prompt = toggle interactive prompting of multiple commands status = status of current connection
Setting up passwordless login for sftp
ssh-keygen -t rsa ssh-copy-id -i ~/.ssh/id_rsa.pub username@remote_host sftp username@remote_host
Display terminal settings
stty -a
Display configuration of system variable
getconf CHILD_MAX
tr also works with these kind of constructions:
tr '[:lower:]' '[:upper:]'Forgetting the 's (single quotes) will cause problems if there is a file in your current directory with the name: l, o, w, e, r, u, p or : Try
touch u && echo tr [:lower] [:upper:]
To remove CRs (^M) from ascii files ftp'd in binary mode from Windows to Linux. An EOF (^Z) remains at the end of the file.
tr -d '\r' < file_with_CR > file_without_CR
Extract a single file from tar archive into the current directory, whitout needing to know the full path (obviously only works if the filename is unique):
tar -xf tarfile --transform='s,.*/,,' $(tar -tf tarfile | grep filename)
You need to be root to run these instructions:
Status of all services:
service --status-all
Restart a service (for example the network service) (similar with start or stop):
service network --full-restart
List all services settings for all runlevels:
chkconfig --list
Example: turn mysql deamon on for runlevels 2 to 5:
chkconfig mysqld on
Stopping and starting gnome:
gdm-stop
gdm-start
Run yum instructions as root:
Clean up packages downloaded by yum:
yum clean packages
Exclude a package from being updated, handy if a package is causing a missing dependency error:
yum update --exclude=package
Make a screenshot of the window in focus in 5 seconds:
gnome-screenshot --window --delay=5
Look up the definition of a word (in English) from the command line:
curl dict://dict.org/d:word
