//Tips tagged cut
Will return only the 1st and 5th columns of a comma-delimited csv file.
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Want to check the amount of used, free and total memory and swap from the command line? This script displays memory and swap information. Fully posix compliant and should work with all 2.[2-6].* kernels .
#fetch and process memory information
[ -f /proc/meminfo ] && {
Buffers=`grep -we 'Buffers' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
Cached=`grep -we 'Cached' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
MemFree=`grep -ie 'MemFree' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
MemTotal=`grep -ie 'MemTotal' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapCached=`grep -ie 'SwapCached' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapFree=`grep -ie 'SwapFree' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
SwapTotal=`grep -ie 'SwapTotal' /proc/meminfo | cut -d' ' -f2- | tr -d "[A-Z][a-z] "`
}
MEMUSED="$(( ( ( ( $MemTotal - $MemFree ) - $Cached ) - $Buffers ) / 1024 ))"
MEMTOTAL="$(( $MemTotal / 1024))"
MEMFREE="$(( $MEMTOTAL - $MEMUSED ))"
MEMPER="$(( ( $MEMUSED * 100 ) / $MEMTOTAL ))"
[ "$SwapTotal" -gt "1" ] && {
SWAPUSED="$(( ( ( $SwapTotal - $SwapFree ) - $SwapCached ) / 1024 ))"
SWAPTOTAL="$(( $SwapTotal / 1024))"
SWAPFREE="$(( $SWAPTOTAL - $SWAPUSED ))"
SWAPPER="$(( ( $SWAPUSED * 100 ) / $SWAPTOTAL ))"
} || {
SWAPUSED="0"
SWAPTOTAL="0"
SWAPPER="0"
}
# display the information
/bin/echo
/bin/echo "Memory"
/bin/echo "Used: $MEMUSED"
/bin/echo "Free: $MEMFREE"
/bin/echo "Total: $MEMTOTAL"
/bin/echo
/bin/echo "Swap"
/bin/echo "Used: $SWAPUSED"
/bin/echo "Free: $SWAPFREE"
/bin/echo "Total: $SWAPTOTAL"
/bin/echo
cut -d: -f1 /etc/passwd | sort OR getent passwd|cut -d: -f1|sort
I use the following to list non-system users. It should be portable though won't work on systems without the getent command.
alias lsusers='getent passwd | tr ":" " " | awk "\$3 >= $(grep UID_MIN /etc/login.defs | cut -d " " -f 2) { print \$1 }" | sort'cut -d"," -f1,5 file.csv > newfile.csv
Will return only the 1st and 5th columns of a comma-delimited csv file.
My little "iso2cd" alias. Not clean, but handy. The Burning device will be auto detected.
example call:
iso2cd debian_lenny_final.iso
alias iso2cd="cdrecord -s dev=`cdrecord --devices 2>&1 | grep "\(rw\|dev=\)" | awk {'print $2'} | cut -f'2' -d'=' | head -n1` gracetime=1 driveropts=burnfree -dao -overburn -v"
example call:
iso2cd debian_lenny_final.iso
alias iso2cd="cdrecord -s dev=`cdrecord --devices 2>&1 | grep "\(rw\|dev=\)" | awk {'print $2'} | cut -f'2' -d'=' | head -n1` gracetime=1 driveropts=burnfree -dao -overburn -v"
The 'read' command can be used to split arguments based on any arbitrary character using IFS:
$ echo 'a/bc/ de fg hi/j' | { IFS='/' read first second others; echo "$first"; echo "$second"; echo "$others"; }
a
bc
de fg hi/j
SSH_COMPLETE=( $(cat ~/.ssh/known_hosts | \
cut -f 1 -d ' ' | \
sed -e s/,.*//g | \
uniq | \
egrep -v [0123456789]) )
complete -o default -W "${SSH_COMPLETE[*]}" ssh